Weird Polygon tool berhavior?

Here's what I do. First, select the Polygon tool in the toolbar with a click of the mouse.

Then click and drag in the middle of the page *without* releasing the mouse.

Initially, the up and down arrow keys increase or decrease the "number of sides". Fine.

But! If I tap and release the space bar then, up and down arrow keys gives a "grid" of Polygons!

Holding the space bar down while tapping the right or left arrow keys turns the Polygon into a star.

Is that what you are getting too?
All under US Keyboard definition. Important.