Cleanup: Comment formatting in interface_panel.c

Also cleaned up some grammar and wording issues, and switched a case
in an if statement to remove a double negative.

1 files changed, 80 insertions, 86 deletions

diff --git a/source/blender/editors/interface/interface_panel.c b/source/blender/editors/interface/interface_panel.c
index aee2529134c..7312c410bba 100644
--- a/source/blender/editors/interface/interface_panel.c
+++ b/source/blender/editors/interface/interface_panel.c
@@ -500,7 +500,7 @@ static bool panel_set_expand_from_list_data_recursive(Panel *panel, short flag,
 
 /**
  * Set the expansion of the panel and its sub-panels from the flag stored by the list data
- * corresponding to this panel. The flag has expansion stored in each bit in depth first
+ * corresponding to each panel. The flag has expansion stored in each bit in depth first
  * order.
  */
 void UI_panel_set_expand_from_list_data(const bContext *C, Panel *panel)
@@ -566,7 +566,7 @@ static void set_panels_list_data_expand_flag(const bContext *C, const ARegion *r
 
     /* Check for #PNL_ACTIVE so we only set the expand flag for active panels. */
     if (panel_type->flag & PNL_INSTANCED && panel->runtime_flag & PNL_ACTIVE) {
-      short expand_flag = 0; /* Initialize to quite complaining compiler, value not used. */
+      short expand_flag;
       short flag_index = 0;
       get_panel_expand_flag(panel, &expand_flag, &flag_index);
       if (panel->type->set_list_data_expand_flag) {
@@ -611,7 +611,7 @@ static void panels_collapse_all(ARegion *region, const Panel *from_panel)
   LISTBASE_FOREACH (Panel *, panel, &region->panels) {
     PanelType *pt = panel->type;
 
-    /* close panels with headers in the same context */
+    /* Close panels with headers in the same context. */
     if (pt && from_pt && !(pt->flag & PNL_NO_HEADER)) {
       if (!pt->context[0] || !from_pt->context[0] || STREQ(pt->context, from_pt->context)) {
         if ((panel->flag & PNL_PIN) || !category || !pt->category[0] ||
@@ -661,11 +661,7 @@ Panel *UI_panel_begin(
   const char *idname = pt->idname;
   const bool newpanel = (panel == NULL);
 
-  if (!newpanel) {
-    panel->type = pt;
-  }
-  else {
-    /* new panel */
+  if (newpanel) {
     panel = MEM_callocN(sizeof(Panel), "new panel");
     panel->type = pt;
     BLI_strncpy(panel->panelname, idname, sizeof(panel->panelname));
@@ -684,11 +680,15 @@ Panel *UI_panel_begin(
 
     BLI_addtail(lb, panel);
   }
+  else {
+    /* Panel already exists. */
+    panel->type = pt;
+  }
 
   /* Do not allow closed panels without headers! Else user could get "disappeared" UI! */
   if ((pt->flag & PNL_NO_HEADER) && (panel->flag & PNL_CLOSED)) {
     panel->flag &= ~PNL_CLOSED;
-    /* Force update of panels' positions! */
+    /* Force update of panels' positions. */
     panel->sizex = 0;
     panel->sizey = 0;
     panel->blocksizex = 0;
@@ -697,9 +697,8 @@ Panel *UI_panel_begin(
 
   BLI_strncpy(panel->drawname, drawname, sizeof(panel->drawname));
 
-  /* if a new panel is added, we insert it right after the panel
-   * that was last added. this way new panels are inserted in the
-   * right place between versions */
+  /* If a new panel is added, we insert it right after the panel that was last added.
+   * This way new panels are inserted in the right place between versions */
   for (panel_last = lb->first; panel_last; panel_last = panel_last->next) {
     if (panel_last->runtime_flag & PNL_LAST_ADDED) {
       BLI_remlink(lb, panel);
@@ -722,7 +721,7 @@ Panel *UI_panel_begin(
     panel_last->runtime_flag &= ~PNL_LAST_ADDED;
   }
 
-  /* assign to block */
+  /* Assign the new panel to the block. */
   block->panel = panel;
   panel->runtime_flag |= PNL_ACTIVE | PNL_LAST_ADDED;
   if (region->alignment == RGN_ALIGN_FLOAT) {
@@ -777,7 +776,7 @@ void UI_panel_end(const ARegion *region, uiBlock *block, int width, int height,
     const int old_sizex = panel->sizex, old_sizey = panel->sizey;
     const int old_region_ofsx = panel->runtime.region_ofsx;
 
-    /* update width/height if non-zero */
+    /* Update width/height if non-zero. */
     if (width != 0) {
       panel->sizex = width;
     }
@@ -785,7 +784,7 @@ void UI_panel_end(const ARegion *region, uiBlock *block, int width, int height,
       panel->sizey = height;
     }
 
-    /* check if we need to do an animation */
+    /* Check if we need to do an animation. */
     if (panel->sizex != old_sizex || panel->sizey != old_sizey) {
       panel->runtime_flag |= PNL_ANIM_ALIGN;
       panel->ofsy += old_sizey - panel->sizey;
@@ -802,7 +801,7 @@ static void ui_offset_panel_block(uiBlock *block)
 {
   const uiStyle *style = UI_style_get_dpi();
 
-  /* compute bounds and offset */
+  /* Compute bounds and offset. */
   ui_block_bounds_calc(block);
 
   const int ofsy = block->panel->sizey - style->panelspace;
@@ -898,12 +897,12 @@ void UI_draw_icon_tri(float x, float y, char dir, const float color[4])
   else if (dir == 't') {
     UI_draw_anti_tria(x - f5, y - f7, x + f5, y - f7, x, y + f3, color);
   }
-  else { /* 'v' = vertical, down */
+  else { /* 'v' = vertical, down. */
     UI_draw_anti_tria(x - f5, y + f3, x + f5, y + f3, x, y - f7, color);
   }
 }
 
-#define PNL_ICON UI_UNIT_X /* could be UI_UNIT_Y too */
+#define PNL_ICON UI_UNIT_X /* Could be UI_UNIT_Y too. */
 
 /* For button layout next to label. */
 void UI_panel_label_offset(uiBlock *block, int *r_x, int *r_y)
@@ -929,10 +928,10 @@ static void ui_draw_aligned_panel_header(const uiStyle *style,
   const bool is_subpanel = (panel->type && panel->type->parent);
   const uiFontStyle *fontstyle = (is_subpanel) ? &style->widgetlabel : &style->paneltitle;
 
-  /* + 0.001f to avoid flirting with float inaccuracy */
+  /* + 0.001f to avoid flirting with float inaccuracy .*/
   const int pnl_icons = (panel->labelofs + (1.1f * PNL_ICON)) / block->aspect + 0.001f;
 
-  /* draw text label */
+  /* Draw text label.s */
   uchar col_title[4];
   panel_title_color_get(
       panel, show_background, is_subpanel, region_search_filter_active, col_title);
@@ -951,7 +950,7 @@ static void ui_draw_aligned_panel_header(const uiStyle *style,
 }
 
 /**
- * Panel integrated in buttons-window, tool/property lists etc
+ * Draw a panel integrated in buttons-window, tool/property lists etc
  */
 void ui_draw_aligned_panel(const uiStyle *style,
                            const uiBlock *block,
@@ -1032,7 +1031,7 @@ void ui_draw_aligned_panel(const uiStyle *style,
     immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
     GPU_blend(GPU_BLEND_ALPHA);
 
-    /* draw with background color */
+    /* Draw with background color. */
     immUniformThemeColor(UI_panel_matches_search_filter(panel) ? TH_MATCH : TH_PANEL_HEADER);
     immRectf(pos, minx, headrect.ymin, rect->xmax, y);
 
@@ -1067,7 +1066,7 @@ void ui_draw_aligned_panel(const uiStyle *style,
     GPU_blend(GPU_BLEND_NONE);
   }
 
-  /* horizontal title */
+  /* Draw the title. */
   rcti titlerect = headrect;
   if (is_subpanel) {
     titlerect.xmin += (0.7f * UI_UNIT_X) / block->aspect + 0.001f;
@@ -1159,7 +1158,7 @@ void ui_draw_aligned_panel(const uiStyle *style,
     immUnbindProgram();
   }
 
-  /* draw collapse icon */
+  /* Draw collapse icon. */
   {
     rctf itemrect = {.xmin = titlerect.xmin,
                      .xmax = itemrect.xmin + BLI_rcti_size_y(&titlerect),
@@ -1196,7 +1195,7 @@ static void imm_buf_append(
   (*index)++;
 }
 
-/* based on UI_draw_roundbox, check on making a version which allows us to skip some sides */
+/* Based on UI_draw_roundbox, check on making a version which allows us to skip some sides. */
 static void ui_panel_category_draw_tab(bool filled,
                                        float minx,
                                        float miny,
@@ -1212,7 +1211,6 @@ static void ui_panel_category_draw_tab(bool filled,
 {
   float vec[4][2] = {{0.195, 0.02}, {0.55, 0.169}, {0.831, 0.45}, {0.98, 0.805}};
 
-  /* Multiply `vec` by radius. */
   for (int a = 0; a < 4; a++) {
     mul_v2_fl(vec[a], rad);
   }
@@ -1234,7 +1232,7 @@ static void ui_panel_category_draw_tab(bool filled,
   uchar cbuf[24][3];
   int buf_index = 0;
 
-  /* start with corner right-top */
+  /* Start right-top corner. */
   if (use_highlight) {
     if (roundboxtype & UI_CNR_TOP_RIGHT) {
       imm_buf_append(vbuf, cbuf, maxx, maxy - rad, col, &buf_index);
@@ -1247,7 +1245,7 @@ static void ui_panel_category_draw_tab(bool filled,
       imm_buf_append(vbuf, cbuf, maxx, maxy, col, &buf_index);
     }
 
-    /* corner left-top */
+    /* Left top-corner. */
     if (roundboxtype & UI_CNR_TOP_LEFT) {
       imm_buf_append(vbuf, cbuf, minx + rad, maxy, col, &buf_index);
       for (int a = 0; a < 4; a++) {
@@ -1265,7 +1263,7 @@ static void ui_panel_category_draw_tab(bool filled,
         vbuf, cbuf, minx, miny + rad, highlight_fade ? col : highlight_fade, &buf_index);
   }
   else {
-    /* corner left-bottom */
+    /* Left bottom-corner. */
     if (roundboxtype & UI_CNR_BOTTOM_LEFT) {
       imm_buf_append(vbuf, cbuf, minx, miny + rad, col, &buf_index);
       for (int a = 0; a < 4; a++) {
@@ -1277,7 +1275,7 @@ static void ui_panel_category_draw_tab(bool filled,
       imm_buf_append(vbuf, cbuf, minx, miny, col, &buf_index);
     }
 
-    /* corner right-bottom */
+    /* Right-bottom corner. */
     if (roundboxtype & UI_CNR_BOTTOM_RIGHT) {
       imm_buf_append(vbuf, cbuf, maxx - rad, miny, col, &buf_index);
       for (int a = 0; a < 4; a++) {
@@ -1313,12 +1311,10 @@ static void ui_panel_category_draw_tab(bool filled,
 }
 
 /**
- * Draw vertical tabs on the left side of the region,
- * one tab per category.
+ * Draw vertical tabs on the left side of the region, one tab per category.
  */
 void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
 {
-  /* no tab outlines for */
   // #define USE_FLAT_INACTIVE
   const bool is_left = RGN_ALIGN_ENUM_FROM_MASK(region->alignment != RGN_ALIGN_RIGHT);
   View2D *v2d = &region->v2d;
@@ -1332,9 +1328,9 @@ void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
   const int px_x_sign = is_left ? px : -px;
   const int category_tabs_width = round_fl_to_int(UI_PANEL_CATEGORY_MARGIN_WIDTH * zoom);
   const float dpi_fac = UI_DPI_FAC;
-  /* padding of tabs around text */
+  /* Padding of tabs around text. */
   const int tab_v_pad_text = round_fl_to_int((2 + ((px * 3) * dpi_fac)) * zoom);
-  /* padding between tabs */
+  /* Padding between tabs. */
   const int tab_v_pad = round_fl_to_int((4 + (2 * px * dpi_fac)) * zoom);
   const float tab_curve_radius = ((px * 3) * dpi_fac) * zoom;
   /* We flip the tab drawing, so always use these flags. */
@@ -1345,27 +1341,27 @@ void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
   bool is_active_prev = false;
 #endif
   float scaletabs = 1.0f;
-  /* same for all tabs */
-  /* intentionally don't scale by 'px' */
+  /* Same for all tabs. */
+  /* Intentionally don't scale by 'px'. */
   const int rct_xmin = is_left ? v2d->mask.xmin + 3 : (v2d->mask.xmax - category_tabs_width);
   const int rct_xmax = is_left ? v2d->mask.xmin + category_tabs_width : (v2d->mask.xmax - 3);
   const int text_v_ofs = (rct_xmax - rct_xmin) * 0.3f;
 
   int y_ofs = tab_v_pad;
 
-  /* Primary theme colors */
+  /* Primary theme colors. */
   uchar theme_col_back[4];
   uchar theme_col_text[3];
   uchar theme_col_text_hi[3];
 
-  /* Tab colors */
+  /* Tab colors. */
   uchar theme_col_tab_bg[4];
   uchar theme_col_tab_active[3];
   uchar theme_col_tab_inactive[3];
 
-  /* Secondary theme colors */
+  /* Secondary theme colors. */
   uchar theme_col_tab_outline[3];
-  uchar theme_col_tab_divider[3]; /* line that divides tabs from the main region */
+  uchar theme_col_tab_divider[3]; /* Line that divides tabs from the main region. */
   uchar theme_col_tab_highlight[3];
   uchar theme_col_tab_highlight_inactive[3];
 
@@ -1430,14 +1426,14 @@ void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
     do_scaletabs = true;
   }
 
-  /* begin drawing */
+  /* Begin drawing. */
   GPU_line_smooth(true);
 
   uint pos = GPU_vertformat_attr_add(
       immVertexFormat(), "pos", GPU_COMP_I32, 2, GPU_FETCH_INT_TO_FLOAT);
   immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
 
-  /* draw the background */
+  /* Draw the background. */
   if (is_alpha) {
     GPU_blend(GPU_BLEND_ALPHA);
     immUniformColor4ubv(theme_col_tab_bg);
@@ -1498,7 +1494,7 @@ void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
                                  NULL,
                                  is_active ? theme_col_tab_active : theme_col_tab_inactive);
 
-      /* Tab outline */
+      /* Tab outline. */
       ui_panel_category_draw_tab(false,
                                  rct->xmin - px_x_sign,
                                  rct->ymin - px,
@@ -1512,7 +1508,7 @@ void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
                                  NULL,
                                  theme_col_tab_outline);
 
-      /* Tab highlight (3d look) */
+      /* Tab highlight (3d look). */
       ui_panel_category_draw_tab(false,
                                  rct->xmin,
                                  rct->ymin,
@@ -1584,7 +1580,7 @@ void UI_panel_category_draw_all(ARegion *region, const char *category_id_active)
 #endif
     immUnbindProgram();
 
-    /* not essential, but allows events to be handled right up until the region edge [#38171] */
+    /* Not essential, but allows events to be handled right up to the region edge (T38171). */
     if (is_left) {
       pc_dyn->rect.xmin = v2d->mask.xmin;
     }
@@ -1729,11 +1725,12 @@ static void align_sub_panels(Panel *panel)
   }
 }
 
-/* this doesn't draw */
-/* returns 1 when it did something */
+/**
+ * Calculate the position and order of panels as they are opened, closed, and dragged.
+ */
 static bool uiAlignPanelStep(ARegion *region, const float fac, const bool drag)
 {
-  /* count active, not tabbed panels */
+  /* Count active panels. */
   int tot = 0;
   LISTBASE_FOREACH (Panel *, panel, &region->panels) {
     if (panel->runtime_flag & PNL_ACTIVE) {
@@ -1745,7 +1742,7 @@ static bool uiAlignPanelStep(ARegion *region, const float fac, const bool drag)
     return 0;
   }
 
-  /* sort panels */
+  /* Sort panels. */
   PanelSort *panelsort = MEM_callocN(tot * sizeof(PanelSort), "panelsort");
 
   PanelSort *ps = panelsort;
@@ -1797,7 +1794,7 @@ static bool uiAlignPanelStep(ARegion *region, const float fac, const bool drag)
     panelsort[tot - 1].panel->ofsx += UI_PANEL_BOX_STYLE_MARGIN;
   }
 
-  /* we interpolate */
+  /* We interpolate. */
   bool changed = false;
   ps = panelsort;
   for (int i = 0; i < tot; i++, ps++) {
@@ -1812,7 +1809,7 @@ static bool uiAlignPanelStep(ARegion *region, const float fac, const bool drag)
     }
   }
 
-  /* set locations for tabbed and sub panels */
+  /* Set locations for tabbed and sub panels. */
   LISTBASE_FOREACH (Panel *, panel, &region->panels) {
     if (panel->runtime_flag & PNL_ACTIVE) {
       if (panel->children.first) {
@@ -1836,7 +1833,7 @@ static void ui_panels_size(ARegion *region, int *r_x, int *r_y)
   int sizex = 0;
   int sizey = 0;
 
-  /* compute size taken up by panels, for setting in view2d */
+  /* Compute size taken up by panels, for setting in view2d. */
   LISTBASE_FOREACH (Panel *, panel, &region->panels) {
     if (panel->runtime_flag & PNL_ACTIVE) {
       const int pa_sizex = panel->ofsx + panel->sizex;
@@ -1866,7 +1863,7 @@ static void ui_do_animate(bContext *C, Panel *panel)
   float fac = (PIL_check_seconds_timer() - data->starttime) / ANIMATION_TIME;
   fac = min_ff(sqrtf(fac), 1.0f);
 
-  /* for max 1 second, interpolate positions */
+  /* For max 1 second, interpolate positions. */
   if (uiAlignPanelStep(region, fac, false)) {
     ED_region_tag_redraw(region);
   }
@@ -1890,8 +1887,6 @@ static void ui_do_animate(bContext *C, Panel *panel)
 
 static void panel_list_clear_active(ListBase *lb)
 {
-  /* set all panels as inactive, so that at the end we know
-   * which ones were used */
   LISTBASE_FOREACH (Panel *, panel, lb) {
     if (panel->runtime_flag & PNL_ACTIVE) {
       panel->runtime_flag = PNL_WAS_ACTIVE;
@@ -1906,10 +1901,10 @@ static void panel_list_clear_active(ListBase *lb)
 
 void UI_panels_begin(const bContext *UNUSED(C), ARegion *region)
 {
+  /* Set all panels as inactive, so that at the end we know which ones were used. */
   panel_list_clear_active(&region->panels);
 }
 
-/* only draws blocks with panels */
 void UI_panels_end(const bContext *C, ARegion *region, int *r_x, int *r_y)
 {
   ScrArea *area = CTX_wm_area(C);
@@ -1925,14 +1920,14 @@ void UI_panels_end(const bContext *C, ARegion *region, int *r_x, int *r_y)
     }
   }
 
-  /* offset contents */
+  /* Offset contents */
   LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
     if (block->active && block->panel) {
       ui_offset_panel_block(block);
     }
   }
 
-  /* re-align, possibly with animation */
+  /* Re-align, possibly with animation. */
   Panel *panel;
   if (panels_need_realign(area, region, &panel)) {
     if (panel) {
@@ -1943,7 +1938,7 @@ void UI_panels_end(const bContext *C, ARegion *region, int *r_x, int *r_y)
     }
   }
 
-  /* tag first panel */
+  /* Tag first panel. */
   Panel *panel_first = NULL;
   LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
     if (block->active && block->panel) {
@@ -1957,7 +1952,7 @@ void UI_panels_end(const bContext *C, ARegion *region, int *r_x, int *r_y)
     panel_first->runtime_flag |= PNL_FIRST;
   }
 
-  /* compute size taken up by panel */
+  /* Compute size taken up by panel. */
   ui_panels_size(region, r_x, r_y);
 }
 
@@ -2032,7 +2027,7 @@ static void ui_do_drag(const bContext *C, const wmEvent *event, Panel *panel)
     panel->ofsy = data->startofsy + dy;
   }
   else {
-    /* reset the panel snapping, to allow dragging away from snapped edges */
+    /* Reset the panel snapping, to allow dragging away from snapped edges. */
     panel->snap = PNL_SNAP_NONE;
 
     /* Add the movement of the view due to edge scrolling while dragging. */
@@ -2103,10 +2098,10 @@ static void ui_panel_drag_collapse(const bContext *C,
     }
     const int oldflag = panel->flag;
 
-    /* lock axis */
+    /* Lock axis. */
     xy_b_block[0] = dragcol_data->xy_init[0];
 
-    /* use cursor coords in block space */
+    /* Use cursor coords in block space. */
     ui_window_to_block_fl(region, block, &xy_a_block[0], &xy_a_block[1]);
     ui_window_to_block_fl(region, block, &xy_b_block[0], &xy_b_block[1]);
 
@@ -2115,12 +2110,12 @@ static void ui_panel_drag_collapse(const bContext *C,
     rect.ymin = rect.ymax;
     rect.ymax = rect.ymin + PNL_HEADER;
 
-    /* touch all panels between last mouse coord and the current one */
+    /* Touch all panels between last mouse coordinate and the current one. */
     if (BLI_rctf_isect_segment(&rect, xy_a_block, xy_b_block)) {
       /* Force panel to open or close. */
       SET_FLAG_FROM_TEST(panel->flag, dragcol_data->was_first_open, PNL_CLOSED);
 
-      /* if panel->flag has changed this means a panel was opened/closed here */
+      /* If panel->flag has changed this means a panel was opened/closed here. */
       if (panel->flag != oldflag) {
         panel_activate_state(C, panel, PANEL_STATE_ANIMATION);
       }
@@ -2131,9 +2126,10 @@ static void ui_panel_drag_collapse(const bContext *C,
 }
 
 /**
- * Panel drag-collapse (modal handler)
- * Clicking and dragging over panels toggles their collapse state based on the panel that was first
- * dragged over. If it was open all affected panels incl the initial one are closed and vice versa.
+ * Panel drag-collapse (modal handler).
+ * Clicking and dragging over panels toggles their collapse state based on the panel
+ * that was first dragged over. If it was open all affected panels including the initial
+ * one are closed and vice versa.
  */
 static int ui_panel_drag_collapse_handler(bContext *C, const wmEvent *event, void *userdata)
 {
@@ -2149,7 +2145,7 @@ static int ui_panel_drag_collapse_handler(bContext *C, const wmEvent *event, voi
       break;
     case LEFTMOUSE:
       if (event->val == KM_RELEASE) {
-        /* done! */
+        /* Done! */
         WM_event_remove_ui_handler(&win->modalhandlers,
                                    ui_panel_drag_collapse_handler,
                                    ui_panel_drag_collapse_handler_remove,
@@ -2157,7 +2153,7 @@ static int ui_panel_drag_collapse_handler(bContext *C, const wmEvent *event, voi
                                    true);
         ui_panel_drag_collapse_handler_remove(C, dragcol_data);
       }
-      /* don't let any left-mouse event fall through! */
+      /* Don't let any left-mouse event fall through! */
       retval = WM_UI_HANDLER_BREAK;
       break;
   }
@@ -2293,7 +2289,7 @@ static void ui_handle_panel_header(const bContext *C,
 
 bool UI_panel_category_is_visible(const ARegion *region)
 {
-  /* more than one */
+  /* Check for more than one category. */
   return region->panels_category.first &&
          region->panels_category.first != region->panels_category.last;
 }
@@ -2330,9 +2326,9 @@ static void ui_panel_category_active_set(ARegion *region, const char *idname, bo
     BLI_addhead(lb, pc_act);
   }
 
-  /* Validate all active panels, we could do this on load,
-   * they are harmless - but we should remove somewhere.
-   * (add-ons could define own and gather cruft over time). */
+  /* Validate all active panels. We could do this on load, they are harmless -
+   * but we should remove them somewhere.
+   * (Add-ons could define panels and gather cruft over time). */
   {
     PanelCategoryStack *pc_act_next;
     /* intentionally skip first */
@@ -2402,7 +2398,7 @@ void UI_panel_category_add(ARegion *region, const char *name)
 
   BLI_strncpy(pc_dyn->idname, name, sizeof(pc_dyn->idname));
 
-  /* 'pc_dyn->rect' must be set on draw */
+  /* 'pc_dyn->rect' must be set on draw. */
 }
 
 void UI_panel_category_clear_all(ARegion *region)
@@ -2420,14 +2416,13 @@ static int ui_handle_panel_category_cycling(const wmEvent *event,
            (event->mval[0] < ((PanelCategoryDyn *)region->panels_category.first)->rect.xmax) :
            (event->mval[0] > ((PanelCategoryDyn *)region->panels_category.first)->rect.xmin));
 
-  /* if mouse is inside non-tab region, ctrl key is required */
+  /* If mouse is inside non-tab region, ctrl key is required. */
   if (is_mousewheel && !event->ctrl && !inside_tabregion) {
     return WM_UI_HANDLER_CONTINUE;
   }
 
   if (active_but && ui_but_supports_cycling(active_but)) {
-    /* skip - exception to make cycling buttons
-     * using ctrl+mousewheel work in tabbed regions */
+    /* Skip - exception to make cycling buttons using ctrl+mousewheel work in tabbed regions. */
   }
   else {
     const char *category = UI_panel_category_active_get(region, false);
@@ -2435,22 +2430,21 @@ static int ui_handle_panel_category_cycling(const wmEvent *event,
       PanelCategoryDyn *pc_dyn = UI_panel_category_find(region, category);
       if (LIKELY(pc_dyn)) {
         if (is_mousewheel) {
-          /* we can probably get rid of this and only allow ctrl+tabbing */
+          /* We can probably get rid of this and only allow ctrl-tabbing. */
           pc_dyn = (event->type == WHEELDOWNMOUSE) ? pc_dyn->next : pc_dyn->prev;
         }
         else {
           const bool backwards = event->shift;
           pc_dyn = backwards ? pc_dyn->prev : pc_dyn->next;
           if (!pc_dyn) {
-            /* proper cyclic behavior,
-             * back to first/last category (only used for ctrl+tab) */
+            /* Proper cyclic behavior, back to first/last category (only used for ctrl+tab). */
             pc_dyn = backwards ? region->panels_category.last : region->panels_category.first;
           }
         }
 
         if (pc_dyn) {
-          /* intentionally don't reset scroll in this case,
-           * this allows for quick browsing between tabs */
+          /* Intentionally don't reset scroll in this case,
+           * allowing for quick browsing between tabs. */
           UI_panel_category_active_set(region, pc_dyn->idname);
           ED_region_tag_redraw(region);
         }
@@ -2629,13 +2623,13 @@ PointerRNA *UI_region_panel_custom_data_under_cursor(const bContext *C, const wm
 /** \name Window Level Modal Panel Interaction
  * \{ */
 
-/* note, this is modal handler and should not swallow events for animation */
+/* Note, this is modal handler and should not swallow events for animation. */
 static int ui_handler_panel(bContext *C, const wmEvent *event, void *userdata)
 {
   Panel *panel = userdata;
   uiHandlePanelData *data = panel->activedata;
 
-  /* verify if we can stop */
+  /* Verify if we can stop. */
   if (event->type == LEFTMOUSE && event->val == KM_RELEASE) {
     panel_activate_state(C, panel, PANEL_STATE_ANIMATION);
   }