Tab captions can degrade GUI performance

[jupe]

This is an issue that has been around for as long as I remember, but only just now have I devoted time to try to investigate the exact cause instead of just using an alternate method to avoid it happening. There are various ways to repro, but most common for me is that if I run something like this in fresh goto "<pickall * '%windir%'>?/ln"; once the results propagate, switching panes, or even worse, maximizing and restoring down the XY window, takes like 4s+ and the whole UI becomes sluggish. With the above repro it should only be a smallish list of ~120 items, larger lists can pretty much make XY seem completely non-responsive and end task worthy. But what I have now discovered is that it's related to the default tab caption, if the tab is renamed to a fixed custom caption then everything returns to normal speed again.

[admin]

Confirmed! Fix comes!