Can't select Tokens using left click

I am having trouble selecting tokens that I set up for the GM to access. I have moved them to the token layer. I can right click them and move them to whatever layer I desire, but I can no longer left click them. As a result a can no longer move them on the map and the three circles (red, green and blue) do not appear. The selection problem seems to happen after i have selected dynamic lighting or fog of war, but this may be unrelated. Any suggestions?

I've run into this a few times. Occasionally it was a browser issue where I just needed to restart. More often though it was because I had hit the keyboard shortcut to switch from the selection tool to another one, usually the pan tool which is the alternate option for the select tool.