ok, so the only time when I was able to produce something similar was when I MMB on the ladder onto a different window, and hit one of the other mouse buttons by mistake. we do have a few issues when you are already dragging and click on another mouse button. the problems with these probably won't be addressed in 077. don't use multiple mouse buttons at the same time!
so I put in a fix that'll be in the next experimental which should reduce this ladder issue, or at the minimum, it'll go away after you click MMB again. hopefully that will help.
the ui redraw problem is an odd one. we are not ruling out a bug, but we can't reproduce it consistently :/. if anyone ever reproduces it consistently do send us the file!