У вашего броузера проблема в совместимости с HTML5
http://extensions.sketchup.com/en/content/s4u-panel
Draw panel by 3 points or select face.
+TAB key :
- normal : Setting panel
- when drawing : Back - Center -Front
+Arrow Down : Back - Center -Front
+Arrow LEFT,RIGHT, UP : Lock direction X,Y,Z
+Enter: Finish
+Hold Shift : lock direction