diff -r 6ce6d3da584f -r 2e0e2c696605 src/editmodes/abstractEditMode.cpp
--- a/src/editmodes/abstractEditMode.cpp	Sat Sep 15 15:57:56 2018 +0300
+++ b/src/editmodes/abstractEditMode.cpp	Fri Dec 21 21:43:06 2018 +0200
@@ -210,7 +210,7 @@
 	if (not config::drawLineLengths())
 		return;
 
-	const QString label = QString::number(abs(v1 - v0), 'f', 2);
+    const QString label = QString::number((v1 - v0).length(), 'f', 2);
 	QPoint origin = QLineF {v0p, v1p}.pointAt(0.5).toPoint();
 	painter.drawText (origin, label);
 }