Well, I believe asking for the conditions was not entirely unjust. We seem to take personal offense quite a lot, don't we!
The reason why I asked is because it does not flicker for me at all (not even when resizing, because I don't have "Show window contents while dragging" enabled on this PC), and that (like Rick said) seems to be the one notable occasion where visible flickering occurs. And due to the way the controls are repainted, there is little one can do about it as such.
The GDI techniques that you pointed out have existed since the 1970s, long before GDI was even planned. The problem is that Code::Blocks is wxWindows based, and double-buffering the UI is not precisely easy (not without a nasty hack, anyway).
One could make a custom toolbar class (like Ceniza said) and draw all the bitmaps by hand, but for the other controls, there is no easy way of doing it really (who feels like designing a tree control from scratch?).
There seems to be heavy overdraw on the wxScintilla component, too. Possibly that could be slightly reduced by changing the container's background (the window background will still draw, so that approach is questionable). But everything that goes beyond that would be quite complicated.
One could remove duplicate redraw events from the message queue, at the cost of a slightly less responsive system, that too would reduce flickering, but again, it is no good and simple solution.
