1. Why specifying negative texture scaling in texture settings is not possible anymore? It made it much easier to make the texture tile seamlessly at corners and edges.
Negative scaling is for reversing the texture (displaying it in the opposite direction). So a scale of 1.0 would display the texture at the created pixel size in the direction it was created. -1.0 would display the texture mirrored at the same pixel size the image was created.
5. (perhaps wrong forum for this question...) I am getting a strange feeling the WED config is getting saved in a wrong way. When running WED, normally I shift Back & Side views a bit to left, and place Object Properties window in the bottom-right corner of te screen. After closing & opening WED, view positions get screwed up. Either 3d view takes 3/4 of screen while everything else is down-scaled, or Back & Side views are set to their original position while their height is increased (so I dont see bottom side of view window, unless I move one up, and make it smaller). Why does it happen, and is it possible to make WED to *not* resave configuration?
Go to Preferences (File>Preferences) and expand the Common Options bar under the Options tab. Make sure the Save Win Positions is NOT checked.
EDIT: Just saw this too:
On the same tab (Options under Preferences) there is a bar at the end called Layout Options. You could try unchecking Auto Default Layout to see if that helps.
I'll leave the other questions to others on the forum who are better able to answer them.
