Problem with case side panel

[Xerlek]

Hello, my case which is a cheap case from amazon, the AvP Defender 400 K2 has a problem, I will soon be cutting a window in the left side panel and would like access to cable management. However, the right side panel is stuck, I got it off once but can't remember how I did it. I am just looking for ideas on how to do it.

 

[Outlander_04]

usually you push them back about a quarter of an inch and then they lift off .

 

[Xerlek]

I forgot to mention that the side panel wont budge