Why are some units highlighted in red?
When 2 or more units overlap on the plan they will turn RED. This indicates an error in your plan.
This can sometimes happen when copy and pasting units.
To resolve this, follow these simple steps.
Select a red highlighted unit from the plan.
If the selected unit is no longer required, you can simply press delete to fix the issue. If the unit is required then move it to an open space on the plan.
This should have resolved the overlapping units. If not, just repeat step 2 until there are no more overlapping units.
You can now reposition the units in the required locations.