Hello, everyone! Bought a prebuilt ~5 months ago with the "Be quiet! pure base 500" case, now i have the need to change something. I loosened the screws on the back and tried pulling the lip but it doesn't work, been struggling with this for about 40 minutes. Strangely enough, loosening the screws and pulling the lip on the identical side panel for the cable management side works perfectly. I also tried removing the screws completely but that didn't help. NOTE: This is the version without a window