I have been trying out PhpStorm for a while now, deciding whether it is worth the money. Things looked good and I really like all its features but at times it slowed down to a grinding halt. Scrolling was nearly impossible and I had to restart it to get back to work again.

I soon figured I wasn't the only one with this problem and a solution is being worked on, but no saying when it'll be done. However my trial was about to end soon and I really started to like PhpStorm. After my trial I downloaded the early access version (EAP) to see if progress was being made with a fix.

Unfortunately no, or well … I'm not sure but I have found a fix using the EAP version which seems to be holding up so far (hours of coding) with no slowdowns. It might work with the latest non-EAP version as well.

How to (possibly) fix it?

Disable the "Show code lens on scrollbar hover" option (search for "code lens" in the preferences) and restart PhpStorm. This should fix the sudden slowdowns!

The preferences window showing the "Show code lens on scrollbar hover" option.

I found this by accident. I always have a lot of files open in split views and one time while hovering gutter I accidentally hovered the scrollbar and the fancy but tediously slow code lens came up. It looked great but I immediately noticed the oh-so-feared slowdown even after it was gone.

Other things to try

Didn't this do the trick for you? Try the following:

Zoom in and out (maybe a couple of times, make sure you zoom out completely).

Try the latest EAP version.

Enable the memory indicator and make sure there is enough free memory.

Disable antialiasing for both the IDE and editor.

Disable the CodeGlance plugin.

Feedback

Please let me know if this worked for you or if you have found another fix that works for you!