Created attachment 370058 [details]
yesterday's package update log

Distribution: Debian testing
Evolution version: 3.26.5-1+b1

Scrolling in the composer stopped working properly recently. I'm pretty sure this happened after yesterday's package update. I'll attach the aptitude log that shows which packages were updated (evolution was not one of them, so maybe the bug is somewhere lower in the stack).

When I scroll in the composer (plain text mode) and then click to set the cursor position, the text area jumps back to roughly where it was before starting to scroll. It seems that the jump is done to bring the old cursor position into view - if I scroll down and click, the topmost line in the new view is the line where the old cursor position was. After the jump, the new cursor position is set according to wherever the mouse happens to point in the new view.

PS. Even worse composer bug has appeared after yesterday's update too: sometimes text gets seemingly randomly deleted just by left-clicking in the text area. I don't have exact steps to reproduce this, so let's ignore that for now.