fix(editor): a block boundary drawn places its signal across only where the other track runs near, the hover and the click count the block signals facing the trains alike, an SHP resonator at a joint finds the piece of a track cut for another one, and a batch of signals missing its template changes nothing but the tracks cut, Ctrl+Z taking them back; the km of each line kept for the hover, the shorter block section named in its warning, the block column wider

application/editormodesignal.cpp

@@ -980,6 +980,13 @@ std::size_t editor_mode::signal_batch(signal_changes const &Changes, std::vector
 		items.push_back(std::move(placing));
 		reads.emplace_back(spot, variant->read.empty() ? std::string{} : editor_includes::substitute(variant->read, {order.name}));
 	}
+	if (false == Error.empty())
+	{
+		// nothing changed but the tracks cut for them, a step of undo
+		if (false == States.empty() || false == Created.empty())
+			push_track_snapshot(std::move(States), std::move(Created));
+		return 0;
+	}
 	// the names passed round among the signals go through ones of their own first, or a read event renamed would be renamed again
 	items.insert(items.end(), Changes.others.begin(), Changes.others.end());
 	EditorSnapshot step;