Fix error when dragging anchors with parent's size == 0
Fix error when dragging anchors with parent's size == 0

MarianoGnu/godot,BastiaanOlij/godot,vkbsb/godot,ZuBsPaCe/godot,akien-mga/godot,Shockblast/godot,Valentactive/godot,pkowal1982/godot,Valentactive/godot,firefly2442/godot,Shockblast/godot,godotengine/godot,godotengine/godot,josempans/godot,Zylann/godot,josempans/godot,Zylann/godot,Zylann/godot,akien-mga/godot,Faless/godot,MarianoGnu/godot,vkbsb/godot,Valentactive/godot,MarianoGnu/godot,DmitriySalnikov/godot,vkbsb/godot,godotengine/godot,ZuBsPaCe/godot,Valentactive/godot,pkowal1982/godot,ZuBsPaCe/godot,vnen/godot,guilhermefelipecgs/godot,vnen/godot,Zylann/godot,honix/godot,akien-mga/godot,DmitriySalnikov/godot,honix/godot,MarianoGnu/godot,Shockblast/godot,Faless/godot,godotengine/godot,BastiaanOlij/godot,vnen/godot,vkbsb/godot,sanikoyes/godot,guilhermefelipecgs/godot,vnen/godot,josempans/godot,guilhermefelipecgs/godot,firefly2442/godot,josempans/godot,akien-mga/godot,sanikoyes/godot,guilhermefelipecgs/godot,guilhermefelipecgs/godot,BastiaanOlij/godot,vnen/godot,vkbsb/godot,josempans/godot,guilhermefelipecgs/godot,firefly2442/godot,BastiaanOlij/godot,sanikoyes/godot,sanikoyes/godot,pkowal1982/godot,MarianoGnu/godot,godotengine/godot,godotengine/godot,vkbsb/godot,pkowal1982/godot,guilhermefelipecgs/godot,josempans/godot,vnen/godot,BastiaanOlij/godot,akien-mga/godot,MarianoGnu/godot,BastiaanOlij/godot,godotengine/godot,firefly2442/godot,josempans/godot,Zylann/godot,sanikoyes/godot,BastiaanOlij/godot,vnen/godot,Valentactive/godot,Shockblast/godot,ZuBsPaCe/godot,Faless/godot,Shockblast/godot,pkowal1982/godot,pkowal1982/godot,firefly2442/godot,DmitriySalnikov/godot,honix/godot,ZuBsPaCe/godot,Shockblast/godot,Valentactive/godot,MarianoGnu/godot,guilhermefelipecgs/godot,Faless/godot,sanikoyes/godot,Valentactive/godot,Valentactive/godot,vkbsb/godot,honix/godot,Faless/godot,firefly2442/godot,Faless/godot,BastiaanOlij/godot,Zylann/godot,ZuBsPaCe/godot,Faless/godot,DmitriySalnikov/godot,Zylann/godot,vnen/godot,josempans/godot,MarianoGnu/godot,honix/godot,honix/godot,Zylann/godot,Shockblast/godot,DmitriySalnikov/godot,pkowal1982/godot,sanikoyes/godot,Shockblast/godot,ZuBsPaCe/godot,akien-mga/godot,firefly2442/godot,pkowal1982/godot,DmitriySalnikov/godot,firefly2442/godot,akien-mga/godot,godotengine/godot,sanikoyes/godot,Faless/godot,akien-mga/godot,ZuBsPaCe/godot,vkbsb/godot,DmitriySalnikov/godot