boolean isDropSiteOk(ProgramNode destinationNode, ProgramNode[] dropNodes,
                         int dropAction, int relativeMousePos) {

        // must be able to drop all nodes, or none at all
        for ( int i = 0; i < dropNodes.length; i++ ) {
            if ( !canDropNode( destinationNode, dropNodes[i], dropAction, relativeMousePos ) ) {
                return false;
            }
        }
        return true;
    }
Return true if the destNode can accept the dropNodes.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/DnDMoveManager.java