Index: /applications/editors/josm/plugins/buildings_tools/src/org/openstreetmap/josm/plugins/buildings_tools/DrawBuildingAction.java
===================================================================
--- /applications/editors/josm/plugins/buildings_tools/src/org/openstreetmap/josm/plugins/buildings_tools/DrawBuildingAction.java	(revision 35822)
+++ /applications/editors/josm/plugins/buildings_tools/src/org/openstreetmap/josm/plugins/buildings_tools/DrawBuildingAction.java	(revision 35823)
@@ -246,5 +246,5 @@
         if (isRectDrawing()) {
             building.setPlaceRect(p);
-            if (building.getLength() < MIN_LEN_WIDTH)
+            if (Math.abs(building.getLength()) < MIN_LEN_WIDTH)
                 return Mode.Drawing;
             return shift ? Mode.DrawingAngFix : Mode.None;