dotnet/wpf · error · InvalidOperationException

Microsoft.Windows.Controls.SR.UIA_OperationCannotBePerformed

Error message

Microsoft.Windows.Controls.SR.UIA_OperationCannotBePerformed

What it means

RibbonTabDataAutomationPeer.RemoveFromSelection() implements ISelectionItemProvider, but WPF's Selector does not support deselecting the currently selected ribbon tab (one tab must always be selected). If the wrapped RibbonTab is currently selected, the method throws InvalidOperationException (SR.UIA_OperationCannotBePerformed) instead of silently deselecting.

Solutions

Do not call RemoveFromSelection on ribbon tabs; select a different tab instead (Select on another tab's peer)
Catch InvalidOperationException and treat as 'cannot deselect the active tab'
Check the tab's IsSelected state (via SelectionItemPattern.SelectionContainer / IsSelected) before calling
Redesign the automation flow so a replacement tab is selected rather than the current one removed

Example fix

// before
((SelectionItemPattern)tabPeer.GetPattern(SelectionItemPattern.Pattern)).RemoveFromSelection();
// after
var sel = (SelectionItemPattern)tabPeer.GetPattern(SelectionItemPattern.Pattern);
if (!sel.IsSelected) { /* no-op allowed */ } else {
    var otherTabPeer = /* peer of a different tab */;
    ((SelectionItemPattern)otherTabPeer.GetPattern(SelectionItemPattern.Pattern)).Select();
}

Defensive patterns

Strategy: validation

Validate before calling

var sel = (SelectionItemPattern)tabPeer.GetPattern(SelectionItemPattern.Pattern);
if (sel.IsSelected) { /* cannot remove: select another tab instead */ return; }

Type guard

bool CanRemoveFromSelection(RibbonTab tab) => !tab.IsSelected;

Try / catch

try { sel.RemoveFromSelection(); }
catch (InvalidOperationException) { /* ribbon tabs cannot be deselected; pick a replacement tab */ }

Prevention

Never call RemoveFromSelection on the active ribbon tab
Switch tabs via Select on another tab's peer
Remember WPF Selector enforces one selected tab
Avoid multi-select assumptions in cross-technology UIA scripts

When it happens

Trigger: Calling RemoveFromSelection() on a ribbon tab's SelectionItem pattern while tab.IsSelected is true.

Common situations: UIA test scripts trying to deselect a tab; cross-framework automation that assumes multi-select or no-selection semantics supported elsewhere.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/c6f6485cc9c82ffd. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/System.Windows.Controls.Ribbon/Microsoft/Windows/Automation/Peers/RibbonTabDataAutomationPeer.cs:146

                // When not minimized
                return ExpandCollapseState.Expanded;
            }
        }

        #endregion

        #region ISelectionItemProvider Members

        /// <summary>
        /// RemoveFromSelection not allowed on currently Selected Tab. No op for other Tabs
        /// </summary>
        void ISelectionItemProvider.RemoveFromSelection()
        {
            RibbonTab tab = GetWrapper() as RibbonTab;
            if (tab != null && tab.IsSelected)
            {
                throw new InvalidOperationException(Microsoft.Windows.Controls.SR.UIA_OperationCannotBePerformed);
            }
        }

        /// <summary>
        /// AddToSelection not allowed. No op if Tab is already selected. 
        /// </summary>
        void ISelectionItemProvider.AddToSelection()
        {
            if (!IsEnabled())
                throw new ElementNotEnabledException();

            Selector parentSelector = (Selector)(ItemsControlAutomationPeer.Owner);
            if ((parentSelector == null) || (parentSelector.SelectedItem != null && parentSelector.SelectedItem != Item))
            {
                throw new InvalidOperationException(Microsoft.Windows.Controls.SR.UIA_OperationCannotBePerformed);
            }
        }

View on GitHub (pinned to 81131a70a4)