diff --git a/src/Gui/QuantitySpinBox.cpp b/src/Gui/QuantitySpinBox.cpp
index 9e8acddaca..1ab6a81e84 100644
--- a/src/Gui/QuantitySpinBox.cpp
+++ b/src/Gui/QuantitySpinBox.cpp
@@ -449,7 +449,7 @@ void QuantitySpinBox::updateEdit(const QString& text)
 
     edit->setText(text);
 
-    cursor = qBound(0, cursor, edit->displayText().size() - d->unitStr.size());
+    cursor = qBound(0, cursor, qMax(0, edit->displayText().size() - d->unitStr.size()));
     if (selsize > 0) {
         edit->setSelection(0, cursor);
     }
diff --git a/src/Gui/TaskCSysDragger.ui b/src/Gui/TaskCSysDragger.ui
index a86539f01d..0371c734a7 100644
--- a/src/Gui/TaskCSysDragger.ui
+++ b/src/Gui/TaskCSysDragger.ui
@@ -126,16 +126,10 @@
          </property>
          <item row="4" column="1">
           <widget class="Gui::QuantitySpinBox" name="zPositionSpinBox">
-           <property name="unit" stdset="0">
-            <string>mm</string>
-           </property>
           </widget>
          </item>
          <item row="2" column="1">
           <widget class="Gui::QuantitySpinBox" name="xPositionSpinBox">
-           <property name="unit" stdset="0">
-            <string>mm</string>
-           </property>
           </widget>
          </item>
          <item row="2" column="0">
@@ -188,9 +182,6 @@
          </item>
          <item row="3" column="1">
           <widget class="Gui::QuantitySpinBox" name="yPositionSpinBox">
-           <property name="unit" stdset="0">
-            <string>mm</string>
-           </property>
           </widget>
          </item>
         </layout>
@@ -370,9 +361,6 @@
       </item>
       <item row="6" column="1">
        <widget class="Gui::QuantitySpinBox" name="translationIncrementSpinBox">
-        <property name="unit" stdset="0">
-         <string>mm</string>
-        </property>
         <property name="minimum">
          <double>0.000000000000000</double>
         </property>