When using non-default font size, the editor has trouble updating after scrolling:
1. Set editor font to Monaco 11 pt
2. Open a source file
3. Scroll down a few lines
4. Click at a line near the middle of the shown lines
See the attached screen shot:
1. Note the clicked line (112) is rendered above its position before the click. And the prior rendering is still on screen.
2. some of the lines below it are only rendered partially (see line 116, 122, and 127, etc)