How do I define the primary monitor in XFCE?

I've set up multiple monitors in xfce per this answer, but my secondary monitor was chosen as the main one. How do I change which monitor is the main one?

Solution 1:

Have you tried installing ARANDR? If you install that, fire it up while root you can drag the screens wherever you want. From there safe configuration and be happy.

Solution 2:

If you have a Nvidia based video card you can use the Nvidia X Server Settings(if you don't have it, you can install it from the synaptic package manager, I think it's called "nvidia-settings-304" in there)

In the X server Display Configuration of Nvidia X Server Settings window you should be able to see all the monitors, change the resolution set the Hz of them. but what's important is that you should see a check box setting stating "Make this the primary display for the X screen". I'm not too sure what the X screen is exactly(I'm not exactly a "rocket scientist" when it comes to computers.) but I know this is what from experience is pretty much what sets the "primary monitor". So basically what ever monitor you have set as the X screen is pretty much the computers "primary" screen and usually denotes what monitor fullscreen games will launch on.

But be warned, some desktop environments like Unity have some less than desirable consequences when setting the X screen to the desired monitor.

Just to let you know, just from previous experience, Unity's launcher can only be on the monitor that is set as the primary display for the x screen. Other desktop environments/shells can also suffer from this problem as their "default" panels and whatnot will jump to another screen if you change what screen is the primary X screen. But I found this to not be as much of a problem as with Unity since most other desktop environments are more flexible with their customization and usually allow users to add panels and whatnot(or could possibly simply allow you to move them like you can with Xfce) on the position and screen you desire or remove them if they are where you don't want them to be.

Solution 3:

From a superuser thread about xfce and primary monitor locations and [this long thread on xfce.org] -- It is a known xfce bug #8328 since 2012 and still open 2014-02.

Suggested workarounds by @pokeeffe include manually moving the panels, believing everyday is opposite day, or fixing the bug in xfce.