I installed the NppFTP plugin and saw one minor issue. When I move the divider line to the right there are many shadows of the divider that persistent for about 1/2 second but the screen goes back to normal. I never got the jitter that you are seeing.

I then enabled word wrap which you seem to be using and there is a slight flicker at times as I drag the divider but no jitter. That prompted me to remove or uninstall NppFTP and to instead see what happens if I make npp a window and to resize it using the dragger in the lower-right corner and moving the mouse in a circle. There is some flicker as the word wrapping does its thing but I never got into a continuous jitter state.

As times over the years I have had applications, including Notepad++ and Firefox, get into a state where it jitters much like what happens at times in your video. The issue is far more common with Firefox. It’s painting the screen and mid-way through painting the code that tries to fit things on the screen realized it’s painted its way into a virtual corner and so it starts painting again using slightly different parameters to get the text to fit, that also gets into a virtual corner and so it tries the first set of parameters again. There’s a loop of repainting two versions of the text.

It’s rare for me and from what I recall tends to happen when I’m resizing an application or the dividers. I suspect it’s an edge condition in text drawing code. The workaround is easy in that I change the size or divider by a pixel.

Reproducing on demand is not easy.

If it’s a very common issue for you and you are willing to put some effort into creating a setup that one of us can 100% duplicate then we may be able to write up steps that allow one of the Notepad++ developers to get the application into the jitter state while also trying to fully understand what bit of code has the edge condition.

Just posting a video isn’t very helpful to help us help you. But I’ve never seen anything as bad as what you showed in the video, so right now, the best I can say is “I cannot reproduce”

Please share/answer the following:

• share your ?-menu’s Debug Info
• click the </> button while making your reply, and paste the smallest amount of example of PHP that causes the problem – and let us know what we can add/remove to make the problem appear/go away.
• does it happen with other types of files, or just PHP?
• what font are you using? does it still happen if you use another font?
  • actually, it might be easiest if you show a screenshots of Settings > Style Configurator > Language: Global Styles for Style: Default Styles and Style: Global Override
• what is your Settings > Preferences > MISC > Use Direct Write? (And if you toggle that option and restart, does the problem still occur?)