Different versions of Internet Explorer seem to have different problems displaying the DLP interface correctly. I was advised to use Firefox instead of IE.
One of the issues we had with a prior version was if you accidentally hit the Back button in the browser instead of the DLP interface's back arrow in the upper right hand corner, I could not see the DLP interface and had to cycle the Enforce server to release my DLP login so I could get back in.
Now that I use Firefox, if I forget and hit the Back button in Firefox, I can just hit the Forward button and see the DLP interface again, and my ID is not locked out of DLP.