Fix folder drag glitch in Firefox

[MorrisJobke]

issue:

• drag'n'drop a folder into the files app in Firefox
• the highlight stays there because Firefox doesn't trigger the drop event for folders

solution:

• behave like the drop event if the dragover event isn't fired for 100ms (only applied in Firefox)

cc @vincchan @rullzer @raghunayyar @LukasReschke

• ref Drag and drop of a folder in firefox gives no feedback #1336

[mention-bot]

@MorrisJobke, thanks for your PR! By analyzing the annotation information on this pull request, we identified @vincchan, @butonic and @luckydonald to be potential reviewers

[nickvergessen]

But the error message still doesnt come anymore? Can we create that as well manually?

[MorrisJobke]

But the error message still doesnt come anymore? Can we create that as well manually?

This is not there in stable9 as well. I would make this an additional PR

[MorrisJobke]

This is not there in stable9 as well. I would make this an additional PR

also in stable8.2 there was no dialog.

I also tried to get an event for the folder drop, but firefox doesn't trigger anything. I guess it simply isn't invoke by Firefox and we can't do much here.

[nickvergessen]

This is not there in stable9 as well. I would make this an additional PR

also in stable8.2 there was no dialog.

Just tested and yes, seems to indeed be broken a long time :(

[nickvergessen]

👍

[nickvergessen]

Review @LukasReschke @MariusBluem

[LukasReschke]

LGTM

[MorrisJobke]

@nickvergessen I guess it's better to backport this to stable10, right?

[nickvergessen]

Yup, quite irritating otherwise