FreeOrion

From the wiki:
Add a binary flag and related checkbox in the options screen to make the game use the default location for the resources directory, rather than using the version stored in config.xml. Currently, if more than one freeorion is installed on a system, and their resources directories contents are incompatible, it's necessary to delete the config.xml every time to make the game use the proper set of resources. With this switch, the game would automatically determine its own resources location (using the existing code that determines the default location of these files) and both versions could be run and would use their own, separate, automatic default locations for the resources dir without requiring the user to update it each time the version is changed.

-Added a checkbox under Options/Directories tab
-With the checkbox enabled you can change your config.xml resource directory to an invalid path and it will still start up
-Command line option --use-default-resource-dir [0 or 1]

I ran into one issue with the DirectoryOption for the resource directory above the check box. It is set up to display the config.xml saved directory when initialized. So that DirectoryOption could possibly be displaying different from what the resource directory is if things are messed up. So I'm now sure how I should work around this? It is purely aesthetic though and doesn't actually effect the functionality of the toggle.

If the use default resource directory check is enabled, then probably there doesn't need to be a visible directory option. Instead, a text control or edit control could be shown in that location that shows what the default location is. Or, see if you can disable the directory option when the check is enabled. This might require some extra code to make sure the dir option and toggle are created at the same time and are aware of eachother, and that signals and such are connected to ensure that toggling on/off the default toggle updates the state of the directory option.

Or, just rename the directory option to "Custom Resource Directory", so that it's clearer that it's only applicable if the use default option is off.

And, that use default resource dir option should probably default to on, as the point is to make things work fine for multiple installs without the user having to change any settings.

Okay I completed these two things. The one thing to note is that Custom Resource Directory is shown in red because I guess it tries to get the initial path to display from it and since Custom Resource Directory is not a valid file path it appears red.

Edit: I just realized should "Custom Resource Directory" be put in the string table to be looked up for when its put in config.xml?

You mean you put "Custom Resource Directory" into the edit box? You probably shouldn't do that; leave it blank, or put the default in the edit box, and instead put "Custom Resource Directory" in a nearby label to explain what the edit box is...
The string "Custom Resource Directory" shouldn't be in config.xml anywhere, but it probably should be in the stringtable so it can be put into the label textcontrol.