OK, while I could not test this with MSBT19x64, I could do it with CLANGx64.

I can now confirm that it is only wchar branch having this issue. In order to reproduce the strange behavior, open theide (wchar) and therein select ide main package. Then open ide.h and select some item in the middle of the Navigator bar lower list. Now, if you start editing the file (e.g. just add one linefeed), and then grab the vertical scroll bar ('elevator') and drag it up or down. Within a second or so, the 'elevator' jumps back into the original 'floor', where your editing was started, and prevents reaching further items in the list.

Best regards,

Tom

EDIT: This also happens on Linux and CLANG. Additionally, I noticed that the Navigator bar lower list keeps refreshing/re-sorting its contents once per second. Discovered that the enumerated items BERRORS, BCALC, ... etc. keep jumping to different order every second.