If the Firefox right click menu (the menu that you get when you right click with the mouse on a web page in a Firefox window or tab) is very slow, taking a long time to appear, the most likely reason for the delay is an add-on or extension.
Try starting Firefox in safe mode. If the problem goes away in safe mode, it was probably an extension causing the issue.
Here's some tips on how to fix that problem, or at least troubleshoot if not solve it.
How to troubleshoot slow rightclick menu in Firefox
First, is the slow down recent? Think back on when it first started happening, say within the last week.
If you can’t remember when, or it was too long ago, then skip to the next section on how to check your Firefox extensions quickly.
If you can remember the date, then identify all Firefox extensions which have been installed or updated since that date. (Go back a few days further than that for luck if you wish.)
If you can't remember which addons are new since that date, how do you work that out? You can check the date from the Addon itself – menu Tools > Add-ons, and on each extension in the popup window it says what the “Install date” is, see this example below (just to show where you can find the Install Date – CLEO wasn’t guilty in my case!). I’ve also highlighted the Disable button:
Go through every one of those extensions that have been added or updated since that date, click Disable for each of them. Restart Firefox. Is the rightclick problem still happening or does the menu come up in a flash now? (Wait a few minutes or an hour just to see, then try the rightlick again).
If the problem’s gone away, then one of those add ons was the culprit. To find which one, enable them one by one – i.e. click on the disabled extension to select it, then click the Enable button, then restart Firefox and check again. Still OK? Enable another one, then restart etc. When it stops working right after you’ve enabled a particular addon, then you’ll know that’s the bad guy, so go and Disable it again. (If you really need it, try checking for an update, or live with the slowness.)
When I had this problem recently, I just disabled all the addon that had been updated or installed in the last few days (like Vanish), and hey presto the problem vanished. I haven’t reenabled them one by one yet, but then I don’t use those particular extensions much, so I’m leaving that job for another time.
How to check your Firefox add-ons / extensions quickly
Here’s a great tip. This trick isn’t original to me, I can’t remember who suggested it to me. But here’s how it works.
- Disable all the first half of your extensions – say if you have 20 extensions, disable the first 10. Then restart and check the rightclick menu (or whatever other Firefox problem you may be having).
- If it’s all fine, then the guilty party is one of those 10; if not, it must be one of the second 10.
- Say it’s one of the first 10. Make sure the first 5 of those are disabled (and re-enable the second 5), then restart and test again. And so on.
This way you can narrow it down to find the problem addon pretty quickly, which will save you having to try each add-on out one by one.