NPE fix for getPathBounds() returning null
Popup menus have rounded corners (without losing the drop shadow.)
Fixed selected tab not painting all the way to the divider.
Don't extend the painting of the leftmost tab, it will look like it gets bigger.
Fixed text field and button placement for editable JComboBox.
Quick demo application

Throwing this together because I can’t seem to get Swing Explorer to
pop up its own window and am wondering what’s going on there.
Ignore crash dumps... which I appear to have quite a few of for some reason.