fix(material/select): overlay offset calculation for disabled option centering

scripts/check-mdc-tests-config.ts

@@ -172,7 +172,8 @@ export const config = {
       'should adjust for the group padding in ltr',
       'should adjust for the group padding in rtl',
       'should not adjust if all options are within a group, except the selected one',
-      'should align the first option to the trigger, if nothing is selected'
+      'should align the first option to the trigger, if nothing is selected',
+      'should not adjust if option centering is disabled any option under a group is selected'
     ],
     'mdc-slide-toggle': [
       // These tests are verifying implementation details that are not relevant for MDC.

src/material/select/select.spec.ts

@@ -4225,6 +4225,25 @@ describe('MatSelect', () => {
               .toBe(Math.floor(triggerTop), 'Expected trigger to align with the first option.');
         }
       }));
+
+      it('should not adjust if option centering is disabled any option under a group is selected',
+        fakeAsync(() => {
+          groupFixture.componentInstance.select.disableOptionCentering = true;
+          groupFixture.componentInstance.control.setValue('oddish-1');
+          groupFixture.detectChanges();
+
+          trigger.click();
+          groupFixture.detectChanges();
+          flush();
+
+          const selected = document.querySelector('.cdk-overlay-pane mat-option.mat-selected')!;
+          const selectedOptionLeft = selected.getBoundingClientRect().left;
+          const triggerLeft = trigger.getBoundingClientRect().left;
+
+          // 16px is the default option padding
+          expect(Math.floor(selectedOptionLeft)).toEqual(Math.floor(triggerLeft - 16));
+        })
+      );
     });
   });
 

src/material/select/select.ts

@@ -1282,6 +1282,8 @@ export class MatSelect extends _MatSelectBase<MatSelectChange> implements OnInit
     // Adjust the offset, depending on the option padding.
     if (this.multiple) {
       offsetX = SELECT_MULTIPLE_PANEL_PADDING_X;
+    } else if (this.disableOptionCentering) {
+      offsetX = SELECT_PANEL_PADDING_X;
     } else {
       let selected = this._selectionModel.selected[0] || this.options.first;
       offsetX = selected && selected.group ? SELECT_PANEL_INDENT_PADDING_X : SELECT_PANEL_PADDING_X;