Ruler annotations disappear when cycling through tools

[tom-osika]

If annotations are drawn with the ruler, then the tool is changed using "", the annotations disappear until the tool is cycled back for to the ruler.

This also holds true for ruler workflows ( #102 ). That is, if a ruler step is specified for part of a workflow, subsequent steps wont have the ruler annotations.

[floryst]

Indeed, this is a limitation with how the current tool affects how you interact with the scene. I think a compromise would be to always draw boxes and rulers, but only support interaction based on the current active tool.