Fix T86331: Preferences menu inaccessible until window resize

The RGN_TYPE_EXECUTE region was zero height - with the "Load & Save"
button drawing outside of those bounds - so it didn't respond to events.

This is because the region started off this size and does not change
with simply adding the buttons. Although it has RGN_FLAG_DYNAMIC_SIZE,
delayed reinit of regions is only currently supported on headers.

This gives the execute region an initial (minimum) vertical size but
also makes the region **hidden** by default.

- Showing Prefs as an editor among others it will show the header
  but not the execute region.

- Showing the Prefs in a popup window, hides the header region
  and shows the execute region.

Ref D10636

1 files changed, 2 insertions, 1 deletions

diff --git a/source/blender/editors/space_userpref/space_userpref.c b/source/blender/editors/space_userpref/space_userpref.c
index d4692f156d3..ceba8ca268d 100644
--- a/source/blender/editors/space_userpref/space_userpref.c
+++ b/source/blender/editors/space_userpref/space_userpref.c
@@ -79,7 +79,7 @@ static SpaceLink *userpref_create(const ScrArea *area, const Scene *UNUSED(scene
   BLI_addtail(&spref->regionbase, region);
   region->regiontype = RGN_TYPE_EXECUTE;
   region->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
-  region->flag |= RGN_FLAG_DYNAMIC_SIZE;
+  region->flag |= RGN_FLAG_DYNAMIC_SIZE | RGN_FLAG_HIDDEN;
 
   /* main region */
   region = MEM_callocN(sizeof(ARegion), "main region for userpref");
@@ -251,6 +251,7 @@ void ED_spacetype_userpref(void)
   /* regions: execution window */
   art = MEM_callocN(sizeof(ARegionType), "spacetype userpref region");
   art->regionid = RGN_TYPE_EXECUTE;
+  art->prefsizey = HEADERY;
   art->init = userpref_execute_region_init;
   art->layout = ED_region_panels_layout;
   art->draw = ED_region_panels_draw;