While editing, I inadvertently activate Expand Track Layers. I don't know how this happens, it seems that Vegas is hypersensitive to double clicking (I've tried to slow down or speed up the double-click speed in Windows without it making any difference).
It happens so often that I'm spending a lot of time selecting Collapse Track Layers (pressing Esc or the keyboard 5 doesn't have any effect, maybe because I'm working off of a laptop rather than a desktop keyboard).
It also takes the system a few seconds each time to repaint the screen layout, so every time it happens there's an interruption and delay in my workflow.
I really don't need to work in A/B mode at all.
So what can I do to disable this feature entirely, e.g. in preferences or by reprogramming what activates it (e.g. a keyboard shortcut rather than a mouse double-click action)?