470286 - Short flicker after activating window if the search bar is focused

Status: RESOLVED FIXED

(Core :: Widget: Cocoa, defect)

Description

[Markus Stange [:mstange]]

Attachment: screenshot of intermediate, half-focused state

Steps to reproduce:
1. Make sure that the search bar is empty.
2. Focus the search bar.
3. Click on the Desktop to unfocus the window
4. Click the window to activate it.

Expected results:
The window's appearance should change from completely unfocused to completely focused in a uniform instant transition.

Actual results:
There's a short flicker created by an intermediate state. See screenshot.

Comment 1

[Ben Turner (not reading bugmail, use the needinfo flag!)]

Easy to see this in debug builds when running something like libgmalloc too.

Comment 2

[Markus Stange [:mstange]]

The screenshot shows that the window is repainted after it has become main but before the "active" attribute has been set on the window. So "natively"-rendered things like unified toolbar and scrollbar have the active appearance, and the rest (which is styled with CSS, dependent on the "active" attribute) still have the inactive appearance.
Also note that the titlebar is still inactive.

-

I think I know what's going on.

When the window is inactive, the "empty" searchbar contains a placeholder text (the name of the search engine).
This is what happens when the window is activated:

- Mac OS X marks the whole window as "needing display"
- NS_ACTIVATE events are sent
  -> the search bar is focused
    -> the placeholder text disappears
      -> a synchronous repaint is invoked         => first repaint, bad
  -> the "active" attribute is set on the window
- drawRect is called (regularly)                  => second repaint, good

So this is just another case of unfortunate synchronous repaints. And the patch in bug 459319 fixes this bug.

Comment 3

[Markus Stange [:mstange]]

Fixed by bug 459319.