fix(ObjectPage): re-expand header on tab switch in IconTabBar mode

In IconTabBar mode, switching tabs while the header was collapsed by
scrolling left the header permanently stuck — scrollTop was reset to 0
but headerCollapsed remained true with no scroll room to trigger
re-expansion.

Reset headerCollapsedInternal to false on tab switch so the header
expands naturally alongside scrollTo({ top: 0 }). The existing
scrollTimeout guard in useObserveHeights already prevents the
programmatic scroll from immediately re-collapsing it.

Also removes the redundant scrollTimeout clause from the spacer height
condition, which was suppressing scroll room during the tab switch
window.

Author: DougDK

packages/main/src/components/ObjectPage/ObjectPage.cy.tsx

@@ -1931,6 +1931,36 @@ describe('ObjectPage', () => {
     cy.findByText('Custom Header Section Two').should('not.be.visible');
     cy.findByText('Subsection1').should('be.visible');
   });
+
+  it('IconTabBar: header re-expands after tab switch when header was collapsed by scrolling', () => {
+    cy.viewport(1440, 900);
+    cy.mount(
+      <ObjectPage
+        data-testid="op"
+        titleArea={DPTitle}
+        headerArea={DPContent}
+        mode={ObjectPageMode.IconTabBar}
+        style={{ height: '100vh', scrollBehavior: 'auto' }}
+      >
+        <ObjectPageSection key="s1" id="s1" titleText="Section 1">
+          <div style={{ height: '2000px', background: 'lightblue' }}>section 1 content</div>
+        </ObjectPageSection>
+        <ObjectPageSection key="s2" id="s2" titleText="Section 2">
+          <div style={{ height: '2000px', background: 'lightyellow' }}>section 2 content</div>
+        </ObjectPageSection>
+      </ObjectPage>,
+    );
+    cy.wait(50);
+
+    // scroll down far enough to collapse the header
+    cy.findByTestId('op').scrollTo(0, 800);
+    cy.get('[data-component-name="ObjectPageHeaderContent"]').should('not.be.visible');
+
+    // switch tabs — header should re-expand and scroll should reset to top
+    cy.get('[ui5-tabcontainer]').findUi5TabByText('Section 2').click();
+    cy.wait(600);
+    cy.get('[data-component-name="ObjectPageHeaderContent"]').should('be.visible');
+  });
 });
 
 const DPTitle = (

packages/main/src/components/ObjectPage/index.tsx

@@ -322,9 +322,9 @@ const ObjectPage = forwardRef<ObjectPageDomRef, ObjectPagePropTypes>((props, ref
       }
       return newSelectionSectionId;
     });
-    // Reset scroll for section swap; scrollTimeout preserves current header collapsed/expanded state.
     if (mode === ObjectPageMode.IconTabBar) {
       scrollTimeout.current = performance.now() + 500;
+      setHeaderCollapsedInternal(false);
       objectPageRef.current?.scrollTo({ top: 0 });
     }
     setTabSelectId(newSelectionSectionId);
@@ -897,8 +897,7 @@ const ObjectPage = forwardRef<ObjectPageDomRef, ObjectPagePropTypes>((props, ref
             style={{
               height:
                 ((headerCollapsed && !headerPinned) || scrolledHeaderExpanded) &&
-                !toggledCollapsedHeaderWasVisible &&
-                !(mode === ObjectPageMode.IconTabBar && scrollTimeout.current >= performance.now())
+                !toggledCollapsedHeaderWasVisible
                   ? `${headerContentHeight}px`
                   : 0,
             }}