Quote - Strange. If I shift-click on a selected polygon, it deselects, but if I shift-click on an un-selected one, it adds it to selection. 8.5 Pro build 243

You are absolutely right.  I don't know if I was thinking of a prior version of Carrara, or some other program, but it seems shift was to add and ctrl was to delete.  Since shift does both, I can deselect again.

Thanks.

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.