With multiple displays: how best to keep the Dock to one side, and on the same display as the menu bar?

I currently have the Dock to the left. In the Displays pane of System Preferences, I have the external display (if present) configured to be on the left side of the main built-in display; and the menu bar on the built-in display.

Problem:

• when I connect an external display, the Dock jumps to it, separating it from the menu bar.

How can I configure the Dock to stay on the main display with the menu bar?

Some things to keep in mind:

1. I prefer the Dock to the left.
2. I don't want it on the right, since that would interfere with the disk icons on the desktop.
3. I don't want it on the bottom, since I have widescreen displays and that would be wasteful of vertical screen real-estate.
4. I can't unusably configure the external display to be on the right side, since it's actually to the left, given the way my desk is setup.

I'm using Mac OS X Lion on a Macbook Pro.

As far as I can find, putting the Dock on the left side of the right monitor or the right side of the left monitor can't be done.

But let's look at other possible solutions to your problem. Point #1 notes that you don't want the dock on the right because it would interfere with disk icons on the desktop. And when you first drag the Dock to the right side, it does indeed cover the disk icons on the right side. But if you select "clean up" on the Desktop once the Dock is positioned on the right, it will move those icons over to make room for the Dock. This is a temporary solution, however, because newly mounted drives will still be buried by the dock. If you select "clean up by name", however, then newly mounted drives will fit into the grid created and not be covered by the Dock.

Not the solution you were looking for, I know, but it might be a workaround.

This question is old but here's how I solved this problem. I have a three monitor and so if I placed the dock right or left it went way too far afield of my main monitor.

A simple but kind-of-clever solution: go to Settings->Display->Arrangement and place your left monitor ABOVE your middle monitor on the virtual arrangement. Now if you choose left side for your dock it stays on the left of the middle monitor.

The only weirdness is that you have to remember to move the mouse "up" to get to the left monitor and "down" to get back to the middle. I find this to be very easy to do... it feels a little awkward for at most five minutes or so.. then it works fine.

I just started doing this so I'm not a 100% sure I'm not going to run into a surprising weirdness, but I can't think of what that would be...

Hold shift while clicking+dragging the resize divider. It will allow you to reposition the dock, including to a different monitor. Though does not allow to place the Dock on a Edge to another Monitor.