problems with attachements

The full editor offers to upload up to 3 files, and signals acceptance with a green checkmark.
I started a new post, loaded 2 small jpg which were accepted, I placed them inine.
The preview showed both in their position, and I could open them.

I corrected a typo and pressed preview. Error message says me that both attachements can’t be found… .
Below, the first file one is still shown (an still with the green check). I pressed delete for this file,
to start up again. Delete did not work. Then I pressed Add Files again - and the browser said silently good bye, text lost.

This problem exists for me quite a while, I wonder if I am the only one who run into it.
Browser is a Windows Firefox 64.0.2 64bit, plugins: only an addblocker, gesturfy and flash.

Again time lost and no way to illustrate a bug report.

There’s a dedicated forum section for forum issues, here: