Is your feature request related to a problem? Please describe.
Sometimes is common that you drag a guide by mistake. This is annoying as you usually want your guides as references (visual and snapping) and don't want them to be moved by mistake.

Describe the solution you'd like
I hope there would be an option to lock the guides. A button close to the ones for "show/hide guide" and "snap yes/no to guide" would be great.

Describe alternatives you've considered
I don't think the following is better but here is an alternative option: to disable the graphical creation of guides by dragging from the ruler and making a simple popup window to create and place the guides...

Additional comments
none

Thanks!