Noticed something strange about cases with plastic windows

In my Fractal Design Arc 2 Midi R2 (with a plastic viewing window on the side panel) I've noticed that the window seems to hold a static charge which attracts dust on the inside and the outside.

I wipe down the window with a dry microfiber cloth on the outside usually once a day or so and on the inside once a week. Not sure if the static electricity is harmful to the guts of my computer and if it's not then I think it's really great.

The inside of the window seems to attract dust and actually keep it there until I wipe it off.

Has anyone else experienced something like this before?

Microfibre + acryllic? nono!