Multiple thumbnails selected

[pedrobmarin]

I have just realised that there is a strange phenomenon that I cannot select one thumbnail, I mean, when I click one thumnail, there are two thumbnails selected. When this happens, the slide update does not work. It happens on Chrome, Edge, and Brave, but NOT on Firefox... This is probably unrelated to this PR. Let me know if I can check something more.

In the video below, I cannot select the thumbnail No.3. When I click it, the thumbnail No.2 is also selected. The time slider updated correctly. But what is shown is actually slide No.2.

Originally posted by @hiroshisuga in https://github.com/bigbluebutton/bbb-playback/issues/160#issuecomment-1020700998