File upload functionality in Firefox doesn't work properly

[GatorsFan]

I agree with @Brickwizard post #11 - reset the browser back to it's original state

 

[Alexzee]

Sometimes working hard pays off. Other times you just know when it's time to reinstall or reset to defaults.
Let us know how things pan out SerchoD.

 

[Condobloke]

But, I cant say the extensions are causing the problem, because I use them normaly, and the problems shoots by 'I don't know what specific condition or action.', But is not directly linked to the instalation of an extension, for example.

9 extensions is over the top. What you have achieved by having that many is introducing an absolute myriad of possibilities.
When the various developers update their extension....you have no idea what they have done and how it will interact with all the other extensions. The possibilities are endless.

Initially, you were perhaps lucky enough for all extensions to get along beautifully. Then something changed.

It is equally possible that a kernel upgrade/update had something to do with this too....not as likely, but still possible.

The fact that you disabled all of the extensions and the problem still existed is worrying to me

The problem is, for example, if you open to write a new Email, in any email, web, etc, you have the clasical Clip Icon to upload files,

I use Thunderbird to open and send emails. I have used it for many years. It does not have a clip icon....instead it has the word Attach up in the composition toolbar, which I can click on and that opens file manager from which I can choose whatever I need to attach to the email.

So, this begs the question....which email provider are you using ? There are, no doubt, interactions between your email provider and your browser. .....or your email provider (either web based or proprietary) has made an alteration/addition/change of code/etc etc....and this perhaps interacting with an extension and causing you grief....

AS I said earlier, the possibilities are endless.

Sticking to the extension apparatus you have is not helpful

Make a plan.
Change browser, investigate whether your email provider updates by itself or if it receives updates via Kubuntu....

I tried turning all of them off, closing Firefox, and reopening it to test,

Was it necessary to close firefox?....did some of the extensions re enable themselves when you closed and then reopened?

There is an answer to this problem....it is likely something simple, not complex.