def getPaneTabUnderCursorOrFirstInstance(paneType):
    """
    Utility function to retrieve a pane tab of a specific type.

    Tries to get the pane tab under the cursor first. If none is found,
    falls back to the first instance of the specified pane type in the current desktop.

    Args:
        pane_type (hou.paneTabType): The type of pane tab to search for.

    Returns:
        hou.PaneTab or None: The found pane tab of the specified type or None if not available.
    """
    desktop = hou.ui.curDesktop()
    paneTab = None

    # Try to get the pane tab under the cursor
    pane = hou.ui.paneTabUnderCursor()
    if pane and pane.type() == paneType:
        paneTab = pane
    else:
        # Fallback to the first instance of the specified type in the desktop
        paneTab = desktop.paneTabOfType(paneType)
    
    return paneTab

def toggleSelectionToolbar():
    with hou.undos.disabler():
        viewport = getPaneTabUnderCursorOrFirstInstance(hou.paneTabType.SceneViewer)
        viewport.showSelectionBar(not viewport.isShowingSelectionBar())

def toggleDisplayToolbar():
    with hou.undos.disabler():
        viewport = getPaneTabUnderCursorOrFirstInstance(hou.paneTabType.SceneViewer)
        viewport.showSelectionBar(not viewport.isShowingDisplayOptionsBar())