FR: Small TreeView tweak

It’d be handy for me if the TreeView component would refresh the size of items (especially item components) when the viewport is scrolled.

Currently resizing the tree causes a poll to TreeViewItem::getItemWidth(), but viewport scrolling does not.

Here’s why I care: I have custom components that I wish to span to the right edge of the tree-view. To make this work I have getItemWidth() do something like:

idealWidth = jmax(textWidth, getOwnerView()->getWidth() - getItemPosition(true).getX());

this works just fine normally and when the tree is resized, but doesn’t track the effect of the item being scrolled left or right.

Ok, I’ll sort something out to do that…