File dialog displays the previously selected file name, which can be of different type

[mitex]

Open some file dialog (for example, File -> Open). Type some text in it, then click "Cancel". Open some other file dialog, for example insert image. The previous text still remains in the file dialog.
This is bad, because the first value can be, for example, "a.sjrb", which is not suitable name when selecting an image file.

[mitex]

[3881], [3882]

[pap]

• Ok but now it doesn't persist the last opened file for the same kind of dialog input. I think this is not the most user-friendly approach but is acceptable
• Commited to trunk at [3895]