I don't think it's affecting all layers, rather that your just seeing it when you switch to other layers? If you it depends on what order you have your layers. Try drawing on a layer then deleting it, post results.
Hi I'm making a map for Dungeons and Dragons using a rather large resolution. 20,000x13,332 @ 300 pixels per inch. My max zoom is @ 164% when I try to just it further the Zoom percentage increases but the image doesn't actually zoom. Which I'm having a hard time adjusting small details with, any ideas on how to increase how far I can zoom?