(1) Great tool!
(2) I've stumbled on a really tricky colour issue, which is only visible
when the player controls are docked at the top:
a black line above the track title (1-px thick, rgb=0,0,0).
Zoomed capture showing the line with "Sample Skin.xml":

It is striking with skins using lighter tones, such as Cheetah DNA:

The black line doesn't top the whole rectangle containing (tile+time+progress bar), but only the part used to display the track title.
The artefact shows up with a series of .XML I've tested:
- Absolute Zero
- AeroBee
- Midnight
- Phred on the lookout
- Sky Blue
- Threshold flat
- Cheetah DNA
- Chameleon DNA
- Blue
- iBee
With skin "MusicBee3", it is visible with both the .XML and .XMLC.
I haven't found any setting explaining this so far
* in
RotemK's guide* in
the wiki * when browsing through the .XML files (especially the PlayerTopFlat and PlayerFlat settings).
Any idea of the possible cause?