Created attachment 181218 [details] screenshot showing a possible empty space next to the rightmost tab, which should not exist I think this is a general Qt issue, so it appears in other Qt apps that use tabs, like qBittorrent, too. I attach a screenshot of what I mean. It is very weird that the right edge of the rightmost tab can be moved. Normally it should always be bound to the screen edge. Instead, it seems the default layout hacks it so that there is a 0px distance, but the user can move the right border of the rightmost tab to the left. To move it back to the right, you need to grab it twice to get it to 0px distance. This is extremely odd, there seems to be no hard border on the right either. So it is possible to move tabs outside of the screen, which also should not happen. This likely requires a fix in upstream Qt, if such behavior is not wanted.
This behaviour is actually wanted. We want users to be able to have empty space on the right end of the view because that area can be used e.g. to right-click the view background. Resizing this empty area also makes sense. Furthermore, extending the right-most column beyond the screen edge is also wanted behaviour, because that last column might contain important information that the user might want to read in full. For this they might need to resize the last column quite a lot. Between all of those, the only thing I would consider a bug is that increasing the size of a column is possible even if none of the items inside the column can make use of that much space. However, this is IMO not a big issue.