I'm using version 0.45 for Windows XP ProI want to make my line width in the Bezier (pen) tool 2 mm. I tried to change this by choosing File->Pen and clicking the "Last used style". Then I edited the stroke properties for an existing line. When I create a new line, the line is invisible (or it does not exist at all, I'm not sure which). Is there a bug? Is there a better way to set the line width?

I partially solved this myself by manually setting the stroke paint color in a line. It still seems hit-or-miss and confusing.

At the top right corner of the screen, when you have the pen tool selected, you'll see the fill and stroke colours that will be used with the path. If they are transparent, then that's why you can't see them. You can easily set the stroke colour by holding Shift and clicking a colour in the colour palette.

Note that "Last used style" will adopt the style last used with any tool. So if you draw a rectangle and make it red with a blue stroke of 4px, then when you draw a path with the pen tool it will have also have a red fill with blue stroke of 4px.