[DiapDealer]

The 6 pixel size difference just means that your preferred working width falls probably below that minimum. Not that the difference in width after reopening Sigil is 6 pixels. The 6 pixels must be enough for the clip bar to believe it needs to display just one more item. And that just one more item is what's visibly expanding Sigil's width to noticeably overlap the other application. Change the UI font size (or the font itself) or shorten one of your clips descriptions, and I'll bet you'll find a combination that works to accommodate your preferred working width.

It may be annoying to you, but it's not a Sigil bug or a defect. It's just that your preferred width happens to have slightly different consequences when it comes to restoring/saving Sigil's widget geometry with the new 6 pixel difference in Sigil's overall width.

The number of clips able to be assigned to each clip bar was also increased in Sigil 2.2.0. The new space available might be hinting to Qt that "just one more clip" is worth expanding ever so slightly to accommodate. Temporarily hide your clips bar(s) and see if your preferred width is maintained. Or remove one of your lesser used clips. Or shorten a clips description. Or lengthen one.