This rewinds the fix for revision 50483.
- the removed code there (as comment said) closes menus on hoovering over another
button in panels. Is unfinished feature to allow quick inspecting menus
by mouse-hold going over menu popup buttons.
- It added yet another check for closing menus - should be done with ->saferct
- The actual bug was simple; the block flag with UI_BLOCK_MOVEMOUSE_QUIT was
accidentally cleared for colorpickers.