Hi chymali. Welcome to the forums :)

Most likely not a bug so I'll move this but let's try to fix the problem before worrying about a tidy forum.

Firstly, maybe it's a browser thing so what browser are you using? You will also need to have javascript enabled because those buttons use javascript to do their thing. If you happen to use a "not everyone has it" browser then perhaps you can switch to something like IE or even better Firefox and see if the problem clears up.

If it is not a browser issue then we'll have to look at figuring out which file is broken. PROBABLY, if it is a corrupted file, you would want to get a brand new copy of 2.4.6 from the 'download' tab, unzip it, delete /plugins/_quicktags.plugin.php from your server, then upload the brand new copy you just unzipped.

If it's not a browser or a file I'd be wondering why ninjas are killing your toolbar, then hire a pirate to take care of the ninjas.

This sounds like [url=http://forums.b2evolution.net/viewtopic.php?t=13392]this[/url] to me.

It's a problem I just live with, I have it on my 1.8.2 installation very occasionally, and on my 2.4.5 installation quite often. It's a Firefox thing, and is something to do with skins. It's very hard to replicate predictably and not everyone suffers it. Look at the error console to see plenty of errors.

Anyone who solves this one will be in line for some major gratitude from me.