Skin debugging and common mistakes

Read the error in its context

Enable the normal Enigma2 debug log and look for [Skin] messages, the screen name and the reported object type. See logs and diagnostics for log locations and GUI options. A parser can log an error and use a fallback, so a screen opening successfully is not enough to prove every attribute worked.

Symptom	First check
Component with name … not found	XML `name` must match the Python `self[...]` GUI component exactly
Source … not found	The screen must register that source, or expose the requested related screen
Converter or renderer not found	Correct case, module/class name and installed package
Attribute error for an object type	The native widget may not implement the handler’s setter
An expected Label is invisible	Size, position, foreground/background colours and `zPosition`; decoration may cover it
Text is clipped	Rectangle height/width, font metrics, padding and wrapping mode
Image is missing	Resolved path, filename case, image format and read permissions
A circle becomes an ellipse	Stretch scaling; compare `scale` with `centerScaled`
A colour looks unexpectedly transparent	Enigma2 XML alpha uses 00 opaque / FF transparent
FHD layout is too large	Coordinates may have been manually scaled as well as scaled by `resolution`
The edited layout has no effect	A later user override may win, or a skin configuration plugin may regenerate the file
Python change has no effect	The old module is still imported; restart the GUI after saving

Validate without pretending to run Enigma2

An ordinary XML parser can catch unmatched tags and malformed attributes:

python3 -c "import xml.etree.ElementTree as E; E.parse('example.xml')"

It cannot prove that source, name, converter arguments or native setters exist. Run the isolated example on the receiver, read the log, then inspect the actual screenshot. The supplied catalogue generator parses Python source with ast; it does not import skin.py into desktop Python.

Make examples reproducible

Keep the XML, its Python component definitions and assets together. Record the source revision, image build and capture resolution. Use fixed sample data when the visual lesson does not need live service data. Change one property at a time for comparisons.

If a main skin becomes unusable, use a known working skin or remove only your own override through SSH while the GUI is stopped. Keep a copy of that override first. Do not replace the entire settings file or factory-reset a receiver just to debug a small XML layout.