5 files changed, 52 insertions, 17 deletions

diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 458fe175fbb..ec6958c8415 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -115,6 +115,7 @@ typedef struct uiLayout uiLayout;
 #define UI_BLOCK_OUT_1			1024
 #define UI_BLOCK_NO_FLIP		2048
 #define UI_BLOCK_POPUP_MEMORY	4096
+#define UI_BLOCK_CLIP_EVENTS	8192	/* stop handling mouse events */
 
 /* uiPopupBlockHandle->menuretval */
 #define UI_RETURN_CANCEL	1       /* cancel all menus cascading */
@@ -364,6 +365,7 @@ void uiTextBoundsBlock(uiBlock *block, int addval);
 void uiPopupBoundsBlock(uiBlock *block, int addval, int mx, int my);
 void uiMenuPopupBoundsBlock(uiBlock *block, int addvall, int mx, int my);
 void uiCenteredBoundsBlock(uiBlock *block, int addval);
+void uiExplicitBoundsBlock(uiBlock *block, int minx, int miny, int maxx, int maxy);
 
 int		uiBlocksGetYMin		(struct ListBase *lb);
 
diff --git a/source/blender/editors/interface/interface.c b/source/blender/editors/interface/interface.c
index 4b7adbc1064..86961cd84dc 100644
--- a/source/blender/editors/interface/interface.c
+++ b/source/blender/editors/interface/interface.c
@@ -434,6 +434,15 @@ void uiCenteredBoundsBlock(uiBlock *block, int addval)
 	block->dobounds= UI_BLOCK_BOUNDS_POPUP_CENTER;
 }
 
+void uiExplicitBoundsBlock(uiBlock *block, int minx, int miny, int maxx, int maxy)
+{
+	block->minx = minx;
+	block->miny = miny;
+	block->maxx = maxx;
+	block->maxy = maxy;
+	block->dobounds = 0;
+}
+
 /* ************** LINK LINE DRAWING  ************* */
 
 /* link line drawing is not part of buttons or theme.. so we stick with it here */
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index 688e8f95ac7..1ba6acf367a 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -5063,6 +5063,14 @@ static uiBut *ui_but_find_mouse_over(ARegion *ar, int x, int y)
 			if(ui_but_contains_pt(but, mx, my))
 				butover= but;
 		}
+
+		/* CLIP_EVENTS prevents the event from reaching other blocks */
+		if (block->flag & UI_BLOCK_CLIP_EVENTS) {
+			/* check if mouse is inside block */
+			if(block->minx <= mx && block->maxx >= mx &&
+			   block->miny <= my && block->maxy >= my)
+				break;
+		}
 	}
 
 	return butover;
diff --git a/source/blender/editors/space_node/drawnode.c b/source/blender/editors/space_node/drawnode.c
index 29f67844827..4e9ac08d8c8 100644
--- a/source/blender/editors/space_node/drawnode.c
+++ b/source/blender/editors/space_node/drawnode.c
@@ -471,6 +471,7 @@ static void node_update_group(const bContext *C, bNodeTree *ntree, bNode *gnode)
 		float locx, locy;
 		rctf *rect= &gnode->totr;
 		float node_group_frame= U.dpi*NODE_GROUP_FRAME/72;
+		float group_header= 26*U.dpi/72;
 		int counter;
 		int dy;
 		
@@ -594,6 +595,15 @@ static void node_update_group(const bContext *C, bNodeTree *ntree, bNode *gnode)
 				gsock = gsock->next;
 			}
 		}
+		
+		/* Set the block bounds to clip mouse events from underlying nodes.
+		 * Add margin for header and input/output columns.
+		 */
+		uiExplicitBoundsBlock(gnode->block,
+							  rect->xmin - node_group_frame,
+							  rect->ymin,
+							  rect->xmax + node_group_frame,
+							  rect->ymax + group_header);
 	}
 }
 
diff --git a/source/blender/editors/space_node/node_draw.c b/source/blender/editors/space_node/node_draw.c
index c4a7f2cb473..024db35a084 100644
--- a/source/blender/editors/space_node/node_draw.c
+++ b/source/blender/editors/space_node/node_draw.c
@@ -197,28 +197,16 @@ static void node_uiblocks_init(const bContext *C, bNodeTree *ntree)
 	bNode *node;
 	char str[32];
 	
-	/* add node uiBlocks in reverse order - prevents events going to overlapping nodes */
+	/* add node uiBlocks in drawing order - prevents events going to overlapping nodes */
 	
-	/* process selected nodes first so they're at the start of the uiblocks list */
-	for(node= ntree->nodes.last; node; node= node->prev) {
-		
-		if (node->flag & NODE_SELECT) {
+	for(node= ntree->nodes.first; node; node=node->next) {
 			/* ui block */
 			sprintf(str, "node buttons %p", (void *)node);
 			node->block= uiBeginBlock(C, CTX_wm_region(C), str, UI_EMBOSS);
 			uiBlockSetHandleFunc(node->block, do_node_internal_buttons, node);
-		}
-	}
-	
-	/* then the rest */
-	for(node= ntree->nodes.last; node; node= node->prev) {
-		
-		if (!(node->flag & (NODE_GROUP_EDIT|NODE_SELECT))) {
-			/* ui block */
-			sprintf(str, "node buttons %p", (void *)node);
-			node->block= uiBeginBlock(C, CTX_wm_region(C), str, UI_EMBOSS);
-			uiBlockSetHandleFunc(node->block, do_node_internal_buttons, node);
-		}
+			
+			/* this cancels events for background nodes */
+			uiBlockSetFlag(node->block, UI_BLOCK_CLIP_EVENTS);
 	}
 }
 
@@ -339,6 +327,15 @@ static void node_update_basis(const bContext *C, bNodeTree *ntree, bNode *node)
 	node->totr.xmax= locx + node->width;
 	node->totr.ymax= locy;
 	node->totr.ymin= MIN2(dy, locy-2*NODE_DY);
+	
+	/* Set the block bounds to clip mouse events from underlying nodes.
+	 * Add a margin for sockets on each side.
+	 */
+	uiExplicitBoundsBlock(node->block,
+						  node->totr.xmin - NODE_SOCKSIZE,
+						  node->totr.ymin,
+						  node->totr.xmax + NODE_SOCKSIZE,
+						  node->totr.ymax);
 }
 
 /* based on settings in node, sets drawing rect info. each redraw! */
@@ -391,6 +388,15 @@ static void node_update_hidden(bNode *node)
 			rad+= drad;
 		}
 	}
+
+	/* Set the block bounds to clip mouse events from underlying nodes.
+	 * Add a margin for sockets on each side.
+	 */
+	uiExplicitBoundsBlock(node->block,
+						  node->totr.xmin - NODE_SOCKSIZE,
+						  node->totr.ymin,
+						  node->totr.xmax + NODE_SOCKSIZE,
+						  node->totr.ymax);
 }
 
 void node_update_default(const bContext *C, bNodeTree *ntree, bNode *node)