When editing screen layouts you drag and drop controls in the (soon to be overhauled by Microsoft) editor. If you end up dragging a bit too aggressively you can actually throw the control off the grid and the visible area.
The funny part is that it’s not easily pulled back in since the editor doesn’t allow you to traverse through the active controls.
Here’s a quick description and fix. First I’ve created a simple layout with a single control:
Then I drag it outside the black area. Notice, that it is no longer visible but not available on the list to the left:
To get it back export the layout to an XML file:
Edit the file in notepad. In this case the file is pretty simple. In real life you’ll be pretty pleased with the search function in Notepad.
The thing to notice here is that the left value has gone negative, since I dragged my control too much to the left:
Change the value to a positive figure and save the document:
Import the layout in the designer
And now the control is visible again:
If you end up with controls out of boundaries, you could close the editor without saving to prevent getting in the above situation.