Lots of trouble selecting pictures in graphs

After having pasted a picture into a graph (or placing it from the picture gallery) I often have trouble selecting it. I click everywhere on it and it never selects. I have run through every layer so it's not that. If I double-click on it, a Modify Draw Environment dialog opens, but the X0, Y0, X1, X2 boxes are blank. 

I would say that this happens about half the time. Any suggestions? MacOS, Igor 8.

What format is the picture: PNG, PDF, ....?

Do you have this problem with other pictures of the same format? What about other pictures with different formats?

Perhaps post your experiment (pxp) and the picture as a ZIP archive so that others can test.