That's happen from time to time. I don't know the reason. Try to click on Reset Default, eventually change the compiler and come back to the default one. May be also, close and reopen C::B. Normally, thats solve this problem.
Correction in debugger_gdbmi_Windows.cbp. zip file was not correctly built
Delete a file submitted by error
Add a paragraph to explain in the paragaph "6.2.6 Building Codeblocks" how to configure global variables when using Codeblocks_Windows.workspace and associated CB projects.
You can find on git or svn a full version of the Windows.cbp (manually synchronised with C::B official versions), with a small documentation : on git : https://github.com/gerard-durand/codeblocks_gd_cbps on svn : https://sourceforge.net/p/codeblocks-gd-cbps/svn/
Small updates
The patch is already included in my C::B installation. It's directly inspired from your debugger_gdbmi_wx33_64.cbp but use global variables instead of hardcoded references. Nevertheless, when I try to open the settings/debugger/default options for GDB/MI the opened window looks empty. Is it normal?
Proposed patch to include gdbmi in _Windows cbps/workspace