Fix/workaround T47685: Drag keymap slider fails

This is a special case where the UI update function re-creases the keymap we're currently editing.
Making it so dragging values fails.

3 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 11dc88d615d..23635096f0f 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -181,6 +181,7 @@ enum {
 	UI_BUT_TIP_FORCE       = (1 << 28),  /* force show tooltips when holding option/alt if U's USER_TOOLTIPS is off */
 	UI_BUT_TEXTEDIT_UPDATE = (1 << 29),  /* when widget is in textedit mode, update value on each char stroke */
 	UI_BUT_SEARCH_UNLINK   = (1 << 30),  /* show unlink for search button */
+	UI_BUT_UPDATE_DELAY    = (1 << 31),  /* don't run updates while dragging (needed in rare cases). */
 };
 
 #define UI_PANEL_WIDTH          340
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index 0ae505777a9..8614fbad8b5 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -7769,7 +7769,9 @@ static void button_activate_init(bContext *C, ARegion *ar, uiBut *but, uiButtonA
 		/* XXX curve is temp */
 	}
 	else {
-		data->interactive = true;
+		if ((but->flag & UI_BUT_UPDATE_DELAY) == 0) {
+			data->interactive = true;
+		}
 	}
 	
 	data->state = BUTTON_STATE_INIT;
diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index e3a749d34f8..1bff2dd7af2 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -3662,6 +3662,9 @@ void uiTemplateKeymapItemProperties(uiLayout *layout, PointerRNA *ptr)
 			/* operator buttons may store props for use (file selector, [#36492]) */
 			if (but->rnaprop) {
 				UI_but_func_set(but, keymap_item_modified, ptr->data, NULL);
+
+				/* Otherwise the keymap will be re-generated which we're trying to edit, see: T47685 */
+				UI_but_flag_enable(but, UI_BUT_UPDATE_DELAY);
 			}
 		}
 	}