Netbeans 12.1 not applying code assistance properly on C headers

Question

I recently updated Netbeans from 12.0 to 12.1 on my Ubuntu 18.04 platform and I have noticed that code assistance has stopped working on C header files (*.h). Among other issues:

• Selecting a hyphenated name like MY_C_MACRO by double clicking on it doesn't work; it only selects a token from the name ("MY", "C" or "MACRO") instead of the whole word.

• Ctrl-clicking on a name doesn't switch to the definition of that name anymore.

• Auto-tabbing doesn't work anymore (hitting ENTER brings the cursor to the beginning of the next line instead of placing it below the previous line's beginning.

• Typing /** and hitting ENTER doesn't automatically insert the template for documenting the symbol below anymore.

Has anyone found the same problem and know how to fix it?