OK, I just found out:
When opening the preferences the first time (=after firefox started) and then cycle through the different categories quite fast, so that I select another category before the current one had a chance to load, the bug occurs.
Those categories, that did not have time to load, are those that do not work afterwards (as described above).
OK, I just found out:
When opening the preferences the first time (=after firefox started) and then cycle through the different categories quite fast, so that I select another category before the current one had a chance to load, the bug occurs.
Those categories, that did not have time to load, are those that do not work afterwards (as described above).