Tools menu sometimes unaccessible
today I wanted to edit an entry. I clicked on the three vertical points and the menu did not appear completely, just the first 10 pixels up to the gray line delimiting each post below "reply quote ^0\/ :" were visible.
It worked again after re-starting the webpage.
The problem appeared just once, so far. I use Firefox 50.1.0 on Windows 10, build 14393.351.
This is not the exact place to make a bug report, if this was your intension. You should check on JIRA and place a report there.
On the other hand, I had also already problems with editing of posts and replies. I could not reply nor add a new thread then. IN my case it was typically after an action on another webpage. This webpage had a problem with my browser (Chrome) and I had to use edge there. Apparently as a consequence of the initial trial on this webpage brought my browser into this state. Possibly you have had a similar issue earlier.