The new Release 20.03 is out! You can download binaries for Windows and many major Linux distros here .
ldd /usr/bin/codeblocks | grep wx
wxWidgets Library (wxGTK port)Version 3.0.2 (Unicode: wchar_t, debug level: 1),compiled at Jun 19 2016 19:25:19Runtime version of toolkit used is 2.24.Compile-time GTK+ version is 2.24.30.Copyright (c) 1995-2013 wxWidgets team
Codeldd /usr/bin/codeblocks | grep wxIs one of the best ways to check what is the version of wx. But I guess it is wx3-gtk2. So the problem is somewhere else.
libwx_gtk2u_core-3.0.so.0 => /usr/lib/x86_64-linux-gnu/libwx_gtk2u_core-3.0.so.0 (0x00007f6c7b42c000)
What theme are you using? Have you tried to use some other window manager?Can you show screen shots?