Hi I love theme and so far it has been working very well for me with limited bugs. However I have one big issue with the design. I frequently accidentally open the themer menu by long pressing the screen when I'm trying to interact with widgets or other on screen elements. It is especially cumbersome when dealing with apps that create on screen overlays . I really like how Nova allows you to choose how to open their menu. Even if you don't change how the menu is opened can you change the long press delay. I feel if it was a little longer, like the stock Google launcher it would be perfect.
Are you sure you are long pressing on the homescreen and not double tapping? You are able to disable the double-tap gesture in the Gesture settings (via the Themer Settings) however the long press gesture is built into the app. In the future this gesture might be added to the gesture list. Sorry for the inconvenience.