How to deactivate visibility of line widths?

Is there anyway to switch off a visibility of line widths?I would apreciate it for more precise drawing. Iwould let it on just for printing.

I know I could set line width to default for each layer, but it is quiet unficient way. I'm used to set line width during creating of each layer. It Looks like a reasonable way for me. But width of line make sense for me mostly just for printing and it's White annoying to use line width during drawing.
So, is there any way to simplify the look of line so that they look like with setting of default line width?

This is also included into 2.2.2 branch..