See the screenshot. You can see that the letters and the characters on the first line are not displayed correctly, there's a small part of the bottom half missing. Reproducible: Always Steps to Reproduce: 1. write/copy some Chinese/Japanese/(...?) characters in Kate. Actual Results: The bottom of all the characters on the line is not displayed. Expected Results: Characters should be displayed correctly.
I got the same behaviour with some invisible character pasted from an email.
The problem also seems to only occur with monospaced fonts.
Known issue: since the painting is line-based fonts whose characters exceed the lower or upper bound of their own line height draw in the area of neighboring lines. When neighboring lines are drawn, these parts are lost. Mostly a problem in the fonts, but then again, would be nice, if Kate could handle it correctly. *** This bug has been marked as a duplicate of bug 335079 ***