Fix knob drag letting events pass through when diff is near zero

Signed-off-by: falkTX <falktx@falktx.com>

dgl/src/EventHandlers.cpp

@@ -441,7 +441,7 @@ struct KnobEventHandler::PrivateData {
         }
 
         if (d_isZero(movDiff))
-            return false;
+            return true;
 
         const float divisor = (ev.mod & kModifierControl) ? accel * 10.f : accel;
         valueTmp += (maximum - minimum) / divisor * movDiff;