fix(interactions): ignore secondary-button cell range drags

cypress/e2e/example-plugin-hybridselectionmodel.cy.ts

@@ -32,6 +32,21 @@ describe('Example - Context Menu Plugin & Hybrid Selection Mode', () => {
     cy.get('#myGrid .slick-cell.selected').should('have.length', 4);
   });
 
+  it('should preserve cell selection when dragging with the secondary mouse button', () => {
+    cy.get('#myGrid .slick-cell.selected').should('have.length', 4);
+
+    cy.get('#myGrid .slick-row[data-row="1"] .slick-cell.l1.r1').trigger('mousedown', {
+      button: 2,
+      which: 3,
+      force: true,
+    });
+    cy.get('#myGrid .slick-row[data-row="3"] .slick-cell.l3.r3')
+      .trigger('mousemove', 'bottomRight')
+      .trigger('mouseup', 'bottomRight', { button: 2, which: 3, force: true });
+
+    cy.get('#myGrid .slick-cell.selected').should('have.length', 4);
+  });
+
   it('should be able to expand the cell selections further to the right', () => {
     cy.get('#myGrid .slick-cell.selected').should('have.length', 4);
     cy.get('#myGrid .slick-row[data-row="2"] .slick-cell.l2.r2')

src/slick.interactions.ts

@@ -84,6 +84,13 @@ export function Draggable(options: DraggableOption) {
   }
 
   function userPressed(event: MouseEvent | TouchEvent | KeyboardEvent) {
+    // Dragging is a primary-button action; allow secondary clicks to continue
+    // to context-menu handling without starting a drag.
+    // Keep synthetic mousedown CustomEvents compatible (they have no `button`).
+    if (event.type === 'mousedown' && 'button' in event && (event as MouseEvent).button !== 0) {
+      return;
+    }
+
     if (!preventDrag(event)) {
       element = event.target as HTMLElement;
       const targetEvent: MouseEvent | Touch = (event as TouchEvent)?.touches?.[0] ?? event;