I now have the July 26th nightly installed and followed all the instuctions in the wiki "Installing Code::Blocks nightly build on Ubuntu".
I still have the same problem with wxFlatNotebook.
Ctrl-Tab does not cycle through the filenames, nor does it choose a file when the keys are released.
The dialog is frozen on the screen until I use the mouse to do a double-click. The first click turns the filename orange, and the second click activates the file.
After the first mouse click, the Ctrl-Tab can again cycles through the file items.

Any ideas?