To add a Link to a element in a model, the user first has to add the Link to the Project Explorer Links tab... using drag and drop (Bravo!). He then has to drag and drop the Link on to the element in the View Window.
What would be great is if the user could drag the Link Target document from MS Explorer onto the host element in Mstn... in one smooth move (using the Alt-modifier).
https://communities.bentley.com/products/microstation/f/microstation-forum/148382/cr-links---drag-and-drop-from-ms-explorer