Annoying popup menu when selecting text, how to remove?

[Cuzit]

First of all, I'm new here. I've been using Linux for about six years now, and I joined this website hoping to learn more about Linux, keep updated with Linux news, and hopefully help others less experienced than me; unfortunately, I spend so much time on Reddit I rarely remember there's a whole Internet how there and I've yet to really visit this website since I registered. I'm posting this in the newbie section because the problem I'm having feels like it probably has a simple solution, but I don't what to do. If this forum is inappropriate, I suppose a mod could move it?

Anyway, upon highlighting a link in either Firefox 4 nightly or Chromium, I get this pop-up menu:

h ttp://i.imgur.com/IRTl0.jpg (please copy paste and remove the space between the h and the t - and yes, this is a "screenshot" taken with a camera, as this menu seems to inhibit the functioning of the PrintScreen key for some reason)

I do not need to click - as soon as a URL is highlighted, the menu pops up, forcing me to click away in order to cancel the menu. At first I assumed it was a Firefox thing - it happens in both 3.6 and 4 Nightly - so I began checking all of my add-ons (only 4) and plugins to see if I have some plugin causing this. Nothing seemed to be. When I switched to Chromium, I quickly realized the same thing happens in Chromium, as well, so it's independent of what browser I'm using. This leads me to believe it's some package I have installed (apt-get, I'm using Linux Mint on this laptop, and on my other computers, which are running Arch, I do not encounter this in either Chromium or Firefox4) that's causing this, so if someone could just identify what package it is I can remove it. Or maybe my assumption is incorrect and there's something else that leads to this popup, but either way, it's really annoying and I want it gone!

Sorry for the wall of text, I tend to type a lot. If you need any more info, just ask. Thanks in advance for any help!

[Lazydog]

I am not using FF4 but I am running FF3.6.13 and I get these because I have installed an add-on called FastestFox.

Not sure if this is standard in FF4 so I would suggest looking at your add-ons and seeing if you have this one installed.

[Cuzit]

It happens in both Chromium and Firefox. I don't have FastestFox installed, as I don't care much for that add-on. It shouldn't be caused by any add-ons, as it happens across browsers (but only in Web Browsers, that I've noticed).

[eilert]

Disappointed to see that your problem are still unsolved Cuzit ..as I have exactly the same problem myself and ours of googling haven't got me any closer to fix this.
All the same in Opera, FF and Konqueror so I expected actions in Klipper to be the cause but its the same thing even after killing Klipper..

There must be a skilled Linux/KDE guru out there who are able to help us out of this M$ kinda problem

[eilert]

Bounce..

Did an upgrade to KDE 4.7 today but no difference.