Can't resize Component Shape in MS Visio 2007

You have to unlock the shape's protection first. After that you will be able to resize the shape. Here is how it is done in Visio 2013:

First you need to enable the Developer Tab in your Visio. Check how it is done here. After that mark your shape with the mouse and go to the Developer Tab, click on protection and uncheck width and height. Now you should be able to resize the shape. It is done similar in Visio 2007, click here.

The grey handles (the little boxes at the corners and middles) definitely mean it's locked. They'd probably be blue otherwise (the default is blue).

So to unlock, first be sure you're in "developer" mode because I'm pretty sure that you can only look at the page if you're not in developer mode. Then right-click on the shape, select "format" from the pop-up, and then "protection". Set protection to "none" (or uncheck one or more protected dimensions/qualities if you don't want to un-protect everything).