Whenever two tabs are beside each-other (For example, Main and Log) If one of the elements is moved away, the remaining element will remain frozen in place, making moving elements around very difficult.
Image example:
Initial configuration.

Moving the log tab away

the main tab, remaining alone in this configuration can no longer be moved again

The only way to move the main tab away would be to put another tab on its side, for example:

and then moving it away

Unsure if this behavior is intended, but its confusing and makes organizing your WebAO UI fairly difficult.
As an additional bug report, in the previous image the "X" to remove the players tab will cease to function.