This dialog is org.eclipse.ui.internal.ide.ChooseWorkspaceDialog
. It does not support any customization and because it is an internal dialog you should not use it in your code.
So it is not possible to change this without breaking the Eclipse API Rules of Engagement
You can set default preferences in the plugin_customization.ini
file in the plugins/org.eclipse.sdk_xxx
directory in your Eclipse install (this applies to all workspaces).