only allow different "from"s if "to" was empty
only allow different "from"s if "to" was empty

damencho/strophejs,strophe/strophejs,diegocr/strophejs,Rom4eg/strophejs,teambox/strophejs,Rom4eg/strophejs,sualko/strophejs,teambox/strophejs,teambox/strophejs,strophe/strophejs,diegocr/strophejs,minddistrict/strophejs,minddistrict/strophejs,ggozad/strophejs,diegocr/strophejs,minddistrict/strophejs,processone/strophejs,sualko/strophejs,m800-limited/strophejs,Voiceworks/strophejs,joachimlindborg/strophejs,processone/strophejs,joachimlindborg/strophejs,damencho/strophejs,damencho/strophejs,joachimlindborg/strophejs,sualko/strophejs,adozenlines/strophejs,Rom4eg/strophejs,m800-limited/strophejs,Voiceworks/strophejs,m800-limited/strophejs,Voiceworks/strophejs,adozenlines/strophejs,processone/strophejs,adozenlines/strophejs,ggozad/strophejs,strophe/strophejs,ggozad/strophejs