The following problems are in latest nightly (revision 1942) but NOT in previous nightly (revision 1940). Using Windows XP x64, default theme (silver).
1. Tabs not painted correctly. See images.Here's how the symbols tab was painted in revision 1940:

And here's how it looks on 1942:

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Selecting the Projects tab and the clicking and holding the mouse button over the Symbols tab creates this effect on Windows (this does not happen in rev 1940):

(Some of the elements from the Symbols are drawn above the Projects tab)
2. Opened filest list flickers when changing active file by clicking the tabs.- Open few files.
- Click the file tabs to view files. The Open files list flickers when tabs are selected.