Instantiate object on mouse click and when cursor IS NOT on UI

Hi!

I am working on some kind of Level Editor and I got a small problem. When you click on the UI to select the current object it instantiates the object anyways. How do I prevent this?

This is currently my code:

 if(Physics.Raycast(ray, out hit, levelEditorSettings.placementRange, levelEditorSettings.placementLayer))
         {
             hitPos = new Vector3(hit.point.x, hit.point.y, hit.point.z);
 
             var temp = hitPos;
             if(levelEditorSettings.enableGrid)
             {
                 temp.x = Mathf.Round (temp.x / levelEditorSettings.gridSize) * levelEditorSettings.gridSize;
                 temp.y = Mathf.Round (temp.y / levelEditorSettings.gridSize) * levelEditorSettings.gridSize;
                 temp.z = Mathf.Round (temp.z / levelEditorSettings.gridSize) * levelEditorSettings.gridSize;
 
                 hitPos = temp;
             }
 
             if(Input.GetMouseButtonDown (0))
             {
                 SpawnObject(spawnThisObject, hitPos);
             }
 
             if(editorMode == 0)
             {
                 DrawCurosr(spawnThisObject, hitPos);
             }
         }