tour:scroll bar not working properly

[DeepikaMalar]

I tried to scroll up and down on tour to select a topic but the scroll window gets disappeared often. It seems not user friendly

[roger-rojas]

I'm experiencing a similar issue using Firefox 71 on Mac Catalina

[mozew]

this style will solve the problem (can use extensions like "stylus" until it's fixed):
.toc > ul { position: relative; z-index: 1; }