Great work, I was looking for this.

however it did not work completely, I had to fiddle the ui-page a litte. (change line 5 and 7 to the following values.) because it gave errors

<g:evaluate var="jvar_table" expression="RP.getWindowProperties().get('sysparm_table')" />

<g:evaluate var="jvar_sys_id" expression="RP.getWindowProperties().get('sysparm_sys_id')" />