Thanks to Andrew and Ben for the help.
Here the Summary:
Original Question:
Does someone know what the different icons in the layer tree represent.
What is their meaning? Is it somewhere documented?
Both actually gave me the same answer.
Andrew pointed me to the following link:
http://www.productview.com/ptcuser/layer-icons.gif
Albert Gschwend
FOTAG GmbH
A. Gschwend
Bühlrain 5
CH-8560 Märstetten
Tel +41 71 659 00 22
Fax +41 71 659 00 23
algsch@bluewin.ch (max.3Mb)