This patch makes the automatic opening of submenus faster by default. I found it unnecessarily slow, especially when I'm in one of the node editors looking through the node categories to find a specific node.

The default value was 2, which meant there was a 200ms delay before submenus would appear. This patch changes that to 100ms.

This setting can be found in Edit > Preferences > Interface > Menus > Open on Moue Over > Sub Level.

Two additional notes:

1. We could change the name of the setting Sub Level to Submenu Auto Open Delay which is more descriptive in my opinion. Currently it is not obvious that the 2 is a unit of time.
2. The Sub Level setting , confusingly, also has effect even when the checkbox for Auto Open is deselected, because submenus always open automatically. So the graying out of Sub Level should probably be removed.