It seems, that C::B experiencing problems in calltips with highlighting of current variable on Windows.
Some more explanation: current variable under cursor should be highlighted. However on a new system (I mean, default settings of C::B) the calltips are displayed in a single black color. The user can change the color for the calltips on Settings->Environment->Colours. It works. However a new user should find it first.
You can test this problem, by temporally renaming your C::B settings folder on "C:Users\YourName\AppData\Roaming\CodeBlocks" (it is hidden folder) and starting C::B.
I looked for this problem. I think, I found: in file C::B/src/sdk/ccmanager.cpp on lines 292 and 293, Calltips foreground is defined as "DimGray, while Calltips background is defined as "DarkBlue". Problem, that on Windows there are no such colors predefined. Changin them to "GRAY" and "BLUE", solve the problem.
Before: lines 292-293
cmgr->RegisterColour(_("Code completion"), _("Tooltip/Calltip foreground"), wxT("cc_tips_fore"), wxColour(wxT("DimGrey")));
cmgr->RegisterColour(_("Code completion"), _("Tooltip/Calltip highlight"), wxT("cc_tips_highlight"), wxColour(wxT("DarkBlue")));
Chage to:
cmgr->RegisterColour(_("Code completion"), _("Tooltip/Calltip foreground"), wxT("cc_tips_fore"), wxColour(wxT("GRAY")));
cmgr->RegisterColour(_("Code completion"), _("Tooltip/Calltip highlight"), wxT("cc_tips_highlight"), wxColour(wxT("BLUE")));
I did not experience this problem on Linux. I guess, that these colors are predefined on Linux.