Issue Description
Elements in my project are now showing pink when I view them in the 3D window.
Solution
Pink elements in Archicad are Inverted Elements.
Inverted elements occur when the top of the element is now below the base of the element. i.e. when you link the top of a wall (a high bulkhead wall) to the storey above. You then adjust the storey height to be lower and now the top link for the wall is below the actual base of the wall.
To find Inverted Elements you can use the Find & Select tool from the Edit Menu. You will find the Inverted Elements as a built-in-criteria set