Index: release/scripts/startup/bl_ui/space_userpref.py
===================================================================
--- release/scripts/startup/bl_ui/space_userpref.py	(revision 38816)
+++ release/scripts/startup/bl_ui/space_userpref.py	(working copy)
@@ -200,6 +200,8 @@
         col.prop(view, "use_rotate_around_active")
         col.prop(view, "use_global_pivot")
         col.prop(view, "use_camera_lock_parent")
+        col.prop(view, "use_lock_split")
+        
 
         col.separator()
 
Index: source/blender/makesdna/DNA_userdef_types.h
===================================================================
--- source/blender/makesdna/DNA_userdef_types.h	(revision 38816)
+++ source/blender/makesdna/DNA_userdef_types.h	(working copy)
@@ -481,6 +481,9 @@
 #define USER_HIDE_RECENT		(1 << 28)
 #define USER_SHOW_THUMBNAILS	(1 << 29)
 
+    
+#define USER_LOCKSPLIT         (1 << 30)
+    
 /* Auto-Keying mode */
 	/* AUTOKEY_ON is a bitflag */
 #define 	AUTOKEY_ON				1
Index: source/blender/makesrna/intern/rna_userdef.c
===================================================================
--- source/blender/makesrna/intern/rna_userdef.c	(revision 38816)
+++ source/blender/makesrna/intern/rna_userdef.c	(working copy)
@@ -2057,6 +2057,13 @@
 	RNA_def_property_boolean_sdna(prop, NULL, "uiflag", USER_LOCKAROUND);
 	RNA_def_property_ui_text(prop, "Global Pivot", "Lock the same rotation/scaling pivot in all 3D Views");
 
+	/* window splitting flag */ 
+	prop= RNA_def_property(srna, "use_lock_split", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "uiflag", USER_LOCKSPLIT);
+	RNA_def_property_ui_text(prop, "Lock Window Splitting", "Lock Window Splitting");
+	RNA_def_property_update(prop, 0, "rna_userdef_update");
+    
+    
 	prop= RNA_def_property(srna, "use_mouse_auto_depth", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "uiflag", USER_ORBIT_ZBUF);
 	RNA_def_property_ui_text(prop, "Auto Depth", "Use the depth under the mouse to improve view pan/rotate/zoom functionality");
Index: source/blender/editors/screen/screen_ops.c
===================================================================
--- source/blender/editors/screen/screen_ops.c	(revision 38816)
+++ source/blender/editors/screen/screen_ops.c	(working copy)
@@ -1294,6 +1294,11 @@
 /* UI callback, adds new handler */
 static int area_split_invoke(bContext *C, wmOperator *op, wmEvent *event)
 {
+	/* dont split, if flag is on */
+	if ( (U.uiflag & USER_LOCKSPLIT) )
+		return OPERATOR_PASS_THROUGH;
+    
+    
 	sAreaSplitData *sd;
 	int dir;
 	
Index: source/blender/editors/screen/screen_edit.c
===================================================================
--- source/blender/editors/screen/screen_edit.c	(revision 38816)
+++ source/blender/editors/screen/screen_edit.c	(working copy)
@@ -1212,9 +1212,10 @@
 			break;
 	
 	if(sa) {
-		if(az->type==AZONE_AREA)
-			WM_cursor_set(win, CURSOR_EDIT);
-		else if(az->type==AZONE_REGION) {
+		if(az->type==AZONE_AREA) {
+			if ( !(U.uiflag & USER_LOCKSPLIT) )
+				WM_cursor_set(win, CURSOR_EDIT);
+		} else if(az->type==AZONE_REGION) {
 			if(az->edge == AE_LEFT_TO_TOPRIGHT || az->edge == AE_RIGHT_TO_TOPLEFT)
 				WM_cursor_set(win, CURSOR_X_MOVE);
 			else
@@ -1301,10 +1302,19 @@
 	if(win && sc && sa) {
 		AZone *az= is_in_area_actionzone(sa, win->eventstate->x, win->eventstate->y);
 		ARegion *ar;
-		
-		if (az && az->type == AZONE_REGION)
-			return 1;
-		
+        
+        if (az) {
+            switch(az->type) {
+                case AZONE_REGION:
+                    return 1;
+                    break;
+                case AZONE_AREA:
+                    if ( (U.uiflag & USER_LOCKSPLIT) )
+                        return 1;
+                    break;
+            }
+		}
+        
 		for(ar= sa->regionbase.first; ar; ar= ar->next)
 			if(ar->swinid == sc->subwinactive)
 				return 1;
Index: source/blender/editors/screen/area.c
===================================================================
--- source/blender/editors/screen/area.c	(revision 38816)
+++ source/blender/editors/screen/area.c	(working copy)
@@ -314,7 +314,8 @@
 		for(az= sa->actionzones.first; az; az= az->next) {
 			if(az->do_draw) {
 				if(az->type==AZONE_AREA) {
-					area_draw_azone(az->x1, az->y1, az->x2, az->y2);
+					if ( !(U.uiflag & USER_LOCKSPLIT) )
+						area_draw_azone(az->x1, az->y1, az->x2, az->y2);
 				} else if(az->type==AZONE_REGION) {
 					
 					if(az->ar) {