Draft GUI setfocus if lengthValue is not visible

If set focus on length instead of x coordinate is checked, Draft set the focus on it also if the lengthValue is not visible

src/Mod/Draft/DraftGui.py

@@ -908,7 +908,7 @@ def redraw(self):
 
     def setFocus(self):
         p = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Draft")
-        if p.GetBool("focusOnLength",False):
+        if p.GetBool("focusOnLength",False) and self.lengthValue.isVisible():
             self.lengthValue.setFocus()
             self.lengthValue.selectAll()
         else: