People will remember my post on column resizing from about a month ago. I did some more work on this over the last few days, based on the nice suggestions left in the comments of that blog entry and some discussions with people. I ended up implementing something which basically only recalculates the expand values when the width of the tree view itself changes, or the number of expand columns. So if the user resizes a column, the expand values will not be changed and the weird/chaotic behavior is gone. You can find the results in the latest patch in the bug (#316087). A small side effect at this moment is that when the expand flag is turned off, the column will be “reset” to use its original requested size (see the last comment in the bug report for some more detail). I am not yet really sure if I like this. Opinions appreciated of course. At this stage I am pretty happy with the behavior, so good chance that this patch will find its way into GTK+ 2.11.x soonish.