I'm not able to replicate the window problem on the slanted walls.
Which version of Archicad are you on
(And please add this to your signature)
Which windows are you using, Archicad or a 3rd party?
As for the sloped wall not trimming the window on the side wall, make a wish if you feel this is an important missing feature.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"