The preferences menu lets you change some settings in the Galaxy Editor. They are organized by category.
Check for Patch When Editor Starts Up
Your host depends on what region you play in, this host will obviously change once the game is released. Hopefully you wont need to mess with it unless you are trying to publish to another region than the one you play in normally (if that is possible).
Invert Mouse Motion: This makes it so that moving up goes down, left goes right, etc. This is only for camera controls like right click + drag to pan the camera.
Translation speed (mouse/keyboard): This is how sensitive the game will be to panning the camera.
Rotation speed (mouse/keyboard): This is how sensitive the game will be to rotating the camera.
Autoscroll when drag-moving the camera to the screen edge: If you suddenly right click + drag the cursor off the edge of the editor window, when this feature is on, it will pan across the map at a rate equal to the set speed. If you turn this feature off, it will instantly take you to the edge of the map.
Autoscroll when dragging selection or brush: If you are drag selecting or holding down left click for a brush, this feature will pan the camera for you so you can get a continuous motion across multiple screen areas.
List of Camera Controls:
Right Click and drag the mouse to pan the camera (move the camera around the map)
Ctrl + Right Click and drag the mouse to rotate the camera orientation.
Alt + Right Click and drag the mouse (vertically) to move the camera up and down on the Z axis only.
Roll the mouse wheel or press Shift + Right Click and drag the mouse to zoom the camera in or out. The mouse wheel is less accurate.
You can also use ctrl + keyboard arrows to zoom in and out (up/down) or to rotate the camera.
Using the keyboard arrow keys normally pans the camera.
Here you can change all of your color settings. These range from the color of editor status text to the color of wireframes and grids to trigger syntax highlighting.
Here you can change your save settings.
Optimize Saving For: You can choose faster saves to make your editor save the map faster. Before you publish or upload your map to the internet you should change this to "Smaller Files" so that it is easier for others to download. Unless you have a very slow computer or a very large map you probably wont notice the difference and should leave "Smaller Files" enabled.
Automatically Save Documents: You can set the editor to periodically save your work in case your computer/editor crashes and you forgot to save. Highly recommended to enable this feature.
Automatically Backup Documents when Saving: You can set the editor to backup your file in case you make an irreversible change, delete it, lock it, or it gets corrupted. The chance of your map getting corrupted is pretty low but it has happened to me and it makes your map unreadable to the editor. You may be able to salvage a corrupted map with an MPQ editor and importing the data into a new map. For this reason, I suggest you turn this on.
Backup File Location: You can choose a special folder to store your backups, or you can leave it in the same directory as the map you are editing.
Include Automatic Saves: Does the autosave feature (if enabled) make backups.
Limit number of Backups per document: This allows you to keep multiple versions of your map as backups in case you want to revert to an earlier version. You should keep this number low if you are worried about disk space or clutter.
The rest should be self-explanitory.
Here you can change your font settings. Grammar Text refers to the trigger editor text size for the bottom window where it summarizes the current item you have selected. Script Code refers to the Galaxy script that you can access from the trigger menu by pressing ctrl + F11.
Undo Limit: This is the number of steps the editor will remember for when you undo multiple actions. The max value is 256, if you have low system memory you may want to decrease this number for better performance. You can undo an action from the menu or by pressing Ctrl + Z at any time. The shortcut for redo is Ctrl + Y.
Display Messages for Undo/Redo Actions: In the message window that pops up for missing assets it will list your undo and redo history if you have this enabled.
Max Frames/Second: Here you can change the frames per second limit. If you have performance problems you should lower these values though anything less than 25fps will not animate smoothly.
Locale: Currently you cannot change this but eventually you may be able to change the default language your map uses for localization purposes.
Here you can change the volume of the editor as well as switch out sounds for specific events.
Here you can change which windows open on start up. For fastest start up times, I recommend starting with "none" for start up documents and only the "terrain" checked under Specific Modules for Startup Windows. If you want the editor to remember where you left off last time, you can change it to "remember previous modules" and "remember previous documents".
If you have a tablet, here are some editor specific adjustments for sensitivity.
When you test a map, it creates a copy for your map in your installation directory (C:/Program Files/Starcraft 2). The default is Test/EditorTest which means it creats a folder called Test and a map called EditorTest.sc2map. You can choose the default difficulty and speed when you are testing, this is useful for testing melee maps.
Use Fixed Random Seed:This feature is very useful if you are testing a random function in your triggers. By using a fixed random seed, any random functions will generate random numbers the same way every time you run your map. This is an easy way to test your random trigger to make sure it is working properly and rule out the effects of your randomness.
Run Game in a Window: This lets you test your map in the windowed mode.
Show Trigger Debugging Window: This window list all of your triggers and variables while you are playing your map so you can monitor what is going on. This feature is not very interactive doesn't seem to be very useful.
Enable Preloading: This decides whether you load certain map assets during the load screen.
You can change your video settings for the editor to either match your in-game settings or to a custom setting that matches your performance requirements.