Bugfix #24801

- Reading 2.4x files could cause print "missing region type".
  Appeared the 2.50 do_versions patch differed from default region
  definitions
- Sometimes editors showed wrong button for type browsing.
  Was because variable wasn't correctly reset on saves.

source/blender/blenloader/intern/readfile.c

@@ -6108,7 +6108,7 @@ static void area_add_window_regions(ScrArea *sa, SpaceLink *sl, ListBase *lb)
 			case SPACE_NODE:
 				ar= MEM_callocN(sizeof(ARegion), "nodetree area for node");
 				BLI_addtail(lb, ar);
-				ar->regiontype= RGN_TYPE_CHANNELS;
+				ar->regiontype= RGN_TYPE_UI;
 				ar->alignment= RGN_ALIGN_LEFT;
 				ar->v2d.scroll = (V2D_SCROLL_RIGHT|V2D_SCROLL_BOTTOM);
 				ar->v2d.flag = V2D_VIEWSYNC_AREA_VERTICAL;
@@ -6357,6 +6357,9 @@ static void do_versions_windowmanager_2_50(bScreen *screen)
 				sl->spacetype= SPACE_INFO;	/* spacedata then matches */
 		}		
 		
+		/* it seems to be possible in 2.5 to have this saved, filewindow probably */
+		sa->butspacetype= sa->spacetype;
+		
 		/* pushed back spaces also need regions! */
 		if(sa->spacedata.first) {
 			sl= sa->spacedata.first;

source/blender/makesdna/DNA_screen_types.h

@@ -214,6 +214,7 @@ typedef struct ARegion {
 #define SCREEN_HANDLER_VERSE	3
 
 /* regiontype, first two are the default set */
+/* Do NOT change order, append on end. Types are hardcoded needed */
 enum {
 	RGN_TYPE_WINDOW = 0,
 	RGN_TYPE_HEADER,

source/blender/makesdna/DNA_space_types.h

@@ -923,6 +923,7 @@ enum {
 
 
 /* space types, moved from DNA_screen_types.h */
+/* Do NOT change order, append on end. types are hardcoded needed */
 enum {
 	SPACE_EMPTY,
 	SPACE_VIEW3D,