handleDragOver = (dragEvent) => {
        if (libraryManager.currentLibrary.isWritable) {
            // Would use dragEvent.dataTransfer here, but can't access that in dragOver events
            const validDropTargets = this.dropTargets && this.dropTargets[dragManager.dragType] || [];
            // Get the offsetTop for the library contents node
            const offsetTop = this.libraryContents.getBoundingClientRect() && this.libraryContents.getBoundingClientRect().top;
            const draggedY = dragEvent.clientY - offsetTop + this._scrollTop;
            const draggedX = dragEvent.clientX;
            // Find the dropTarget we are dragging over
            // TODO: This needs to be optimized. Slow for a lot of elements.
            const activeDropTarget = validDropTargets.find(dropTarget => {
                const isInYBounds = draggedY >= dropTarget.y && draggedY <= dropTarget.y + dropTarget.height;
                const isInXBounds = draggedX >= dropTarget.x && draggedX <= dropTarget.x + dropTarget.width;

                return isInYBounds && isInXBounds;
            });

            // Set or reset the drag manager drop target
            dragManager.setActiveDropTarget(activeDropTarget);
        }
    }