[solved] Cannot post attachments with Firefox

[Elvish_Hunter]

Some days ago, I noticed a problem. I needed to attach a file to a post, so I clicked on the Browse button that can be found in the Upload attachment section of the posting form. To my surprise, nothing happened: the file selection dialog didn't appear, nor did I get an error message. Exactly nothing, like it was a button without a defined behavior.
This happens to me both on Linux Xubuntu, with Firefox 37.0.2, and on Windows 7, with Firefox Developer Edition 39.0.2a and no extensions installed. However, everything works fine on Xubuntu with Chrome 42.

[Iris]

If you can see this it means it works for me on Firefox 37.0.2 on Debian 8.

7902.png (95.83 KiB) Viewed 3249 times

[Ravana]

I believe this is browsers general problem, not related to forums. With chrome I have noticed that sometimes no upload OR download dialogs show up, at least until browser restart.

[Elvish_Hunter]

If you can see this it means it works for me on Firefox 37.0.2 on Debian 8.

Thanks, this was really useful because it restricted the issues to my setups. After you posted it, I remembered that, due to security reasons, I modified a settings in about:config in both installations. Namely, I emptied the dom.popup_allowed_events property, to block all popups: restoring it to the default value (change click dblclick mouseup reset submit touchend) fixed the issue.
That's weird, however, given that a file selection dialog isn't a popup...