For big projects (here autotool project), when opening a file, everything except basic C++ token could remain white. Hover the mouse does not show any information about the word (object, function...). Sometimes only few words of the all file will be recognized. Reloading the file (F5 or right-click then reload on the file tab) will often make the recognition to work again, but not all the time. On Debian Linux Buster, Xfce, kdevelop 5.3.1 appImage. This issue is redundant since most versions of kdevelop (all 4.x, all 5.x) and probably even older ones.
When using kdevelop for a long (ie several hours or even more) without interrupting (no kdevelop restart, no reboot), such a thing could happen: file a.cpp is well recognized at the beginning of the session. Edit other files (a.cpp can be kept in a tab or be closed). Later on, come back to edit a.cpp, some functions, namespaces or classes are not recognized anymore. Or the full file is completely full of white words.
A more weird thing is that on some files, a function call might be recognized (it will be colorized and mouse hover on it will give information), but some lines later in the same file, the exact same function call will be completely white and without anything shown by mouse hover. On some headers, adding a comment, changing a comment, removing a comment will lead to a complete white header (#ifndef and #define will also not be recognized). For these situations, reloading the file 5 or 10 times might resolve the issue. As other issues I suspect the background parser is responsible of this. I can show pictures if that could help.
Created attachment 117762 [details] Statement white line Little capture to show that the first line with "ubo.BufferSubData" is well recognized (hovering it shows all information) whereas in the last function, in the same file and class, the exact same call is not recognized at all (nothing happens when hovering it).