If you’re anything like me, as soon as you connect your laptop to an external display you’ll end up moving your applications around into a better position and size so that you can work happily. Then, when you disconnect your external display to go back onto the road OSX will do its best to put them somewhere sensible on your smaller laptop screen, but fails horribly.

Enter Cordless Dog’s “Stay” application.

Stay is a deceptively simple (at least the way I’m using it) application that lives in your Mac’s taskbar. First, set up your applications so that they’re positioned as you want them, then choose “Store Windows for all Applications” from the app’s dropdown menu. If you then want to restore applications to their stored position just pull down the menu again and choose “Restore Windows”. Simple.

To make things even more simple though, pop open the application preferences. There aren’t many options here (and there don’t need to be), but for my money it makes sense to turn on “Start Stay at login”, “Restore Windows as displays are connected and disconnected” and “Restore Windows as applications are launched”. And suddenly, as if by magic, application positioning with multiple displays starts working in the way it always should have done.

Cordless Dog’s “Stay” application costs a measly $15, and is worth every cent. Good job, Cordless Dog chaps!

UPDATE

As David Thompson pointed out, I should probably point out that currently Stay and Spaces don’t currently live marvellously happily together. If you’re a user of Spaces (I’m not), you should probably wait for a future release of Stay.

The way I do this is to use a “hot corner”. In OSX you can set up your Mac to perform different tasks when you move your mouse up to any one of the four corners. If you open System Preferences, then Exposé and Spaces and make sure you’ve got the Spaces tab open you’ll see an Active Screen Corners section at the top of the window. I have the bottom right hand corner set to Start Screen Saver. Because I have set Require password to wake this computer from sleep or screen saver in the Security section of System Preferences, when I throw my mouse into the bottom right hand corner of the screen it automatically locks itself for me.

It’s a simple solution that works well for me.

Another way you can lock your machine is to use the Keychain Access application (/Applications/Utilities/Keychain Access.app). If you load this and then open Preferences you’ll see a Show Status in Menu Bar option on the General tab. If you tick this you’ll see an unlocked padlock appear in your menu bar. From now on if you want to lock your machine you can click on the padlock icon and then select Lock Screen. I personally don’t use this solution because it requires more dexterity than just throwing the mouse into a corner of the screen, but it’s another option that you might lie to use.

So, there you have it — two different ways of locking your Mac’s screen under OSX.