Height and width set in XML have just been ignored (they were expected
as option nodes, not attributes).
This has been fixed. Please revisit your spacer sizes...

'Alternative' panels. Better error messages.

Now for nodes where we know that the performance saving workaround
makes sense, we can explicitly set it in the attributes. By default,
all children are built. Result: E. g. GEO_HEAT will be filled correctly
even if it's not used because SNP_SOIL is FALSE (without having to state
that it should work in the XML).

Skip over comments before root node, add 'open in editor' context menu for XMLs, show the application's name in the title, shortcuts for 'row' and 'column', add Spacer panel, smaller layout fixes