Rhino render mesh bug and slow working in wireframe and shaded mode

Hi guys, im having a bug in one of my rhino files.

there is always a render mesh wireframe visible. tried clear all render meshes and played around with the render mesh setting.

and the workflow got at some point realy slow / laggy

the file i m working on is by far to big for my pc to handle - 350mb

im on rhino 7 latest version

graphic card nvidia geforce rtx 2060Ti 8gb
cpu amd ryzen 9 3800
ram 32gb

any suggestion to solve the issue

try resetting your view mode to default?