This policy turns off the insert a space after selecting a text prediction option. This does not however prevent the user or an application from changing the setting programmatically. The insert a space after selecting a text prediction option controls whether or not a space will be inserted after the user selects a text prediction candidate when using the on-screen keyboard. If the policy is Enabled then the option will be locked to not insert a space after selecting a text prediction. If the policy is Disabled or Not Configured then the user will be free to change the setting according to their preference. Note that the availability and function of this setting is dependent on supported languages being enabled.
Control Panel\Regional and Language Options
At least Windows Vista