Another drag and drop problem, this time with Firefox

Hello I have another problem with drag and drop, it may be a bug but... I don't know how to trace it precisely. Generally in Firefox until version 48, dragging an URL icon (favicon in address bar) to desktop caused opening a menu which allowed to save or link (create .desktop launcher) to a site. This still works in later versions of Firefox in XFCE and MATE, but in TDE since version 48 it started to behave differently: Now Konqueror asks for filename, and then saves just a text file with url as text, and these files are unusable as launchers. This is probably not a Firefox problem, as this dragging still works well in MATE and XFCE without problems. The problem is present only in TDE. Is it possible to give a template to... I don't know, Konqueror?, how to create .desktop file for a specific application or content type? Or is it a problem with not full drag and drop implementation? MCbx