Thanks! This is a huge improvement in terms of functionality.
But the coloring of the selector seems to be optimized only for some light skins. It doesn't look good with most of dark skins and leaves a lot to be desired.
1. Why not simply use default border elements just like other pop-up dialogs?
2. Tick mark is colored inverted with dark skins.
3. Why not use the same colors as the previous field selector for tick mark and tick box?
4. Most serious issue. When you're dragging a new field to between existing fields, the insert line is invisible with many skins.
5. When trying to close it down, I keep moving the mouse to top-right corner, looking for close(x) button just like with other pop-up dialogs.