Upon occasion you will find that you can no longer select form objects with your mouse, in most cases the cause of this behavior has something to do with grouping and then un grouping said objects.

To correct this behavior you will need to use the object explorer which can be found while designing your form under View + Object Explorer.

Once you have opened the Object Explorer you can browse the objects in the left window and click the select object button to give said object focus.

Unfortunately the object will still be un selectable when you close the object explorer therefore it is necessary to cut and then paste the object back to the canvas.

Now return the object to it's original position on the canvas and it is selectable once again!