now my toolbars are corrupted in a way that they are far too wide
I have experienced this. But only because I was fooling around
with the toolbars code and specifying wxWindow::SetToolBar(m_pToolbar).
It caused the same problem.
But I dont see how just changing libs causes it. Have you tried
a "clean" CB re-build. Ie, trash the ...\output ...\devel directories
and re-build?