TTreeList buttons/icons

the demos provided with our install show the buttons as being a rectangle with a plus or minus sign inside.

when using the component in Delphi XE I am seeing a triangle for 1st and 2nd level and just a small line on others. I would like the rectangle with + or - in all. I have set every property the same as the demo but still no change.
both component's version are
thank you,