The "Find" function is soon to be your best friend ever.
In Edit mode (I guess you can do this in Gesture mode too, I just typically do it when I'm in Edit mode) select the control whose parent you would like to find (when it is selected, it is outlined in red).
Go to Edit > Find... (or just hold down the Ctrl key and press the F key (Ctrl+F)), this will open up the "Find..." window.
In the top combo box scroll down to and select "controls". After selecting this, you will see that the option fields below this combo box change to "Device ID" and "RUID". If you properly selected a control before opening the Find... window, these fields should be automatically populated with the Device ID and RUID for that specific control. If this is true, you can click on OK or just hit the Enter key on your keyboard. If they are not automatically populated, cancel out of the Find... window and try again.
You should see the "Find Results" tab at the bottom of the screen now lists all instances of that specific control in the project file. These are links that you can click on to find all those controls. If you delete controls from the project file they will be removed from this list. As you are clicking through the links to find all the controls, you will find the original device somewhere in the project file. If it is in a hidden or locked page, you will have to un-hide or unlock the page to be able to see it, but the block it is located within will be highlighted on the screen.
To clear this highlighting, you can right click in the main window anywhere and choose "Clear Find Highlight" near the bottom of the right click menu. You can also click in the Find Results tab away from the links and the highlighting will be cleared.
Once you start using the keyboard shortcuts to get around, you will find that you can cover a lot of ground very quickly and it will become pretty obvious how project was assembled.
Have fun out there!
Josh Millward
Burnt Orange Studios