With the Iwidgets test suite:

$ make test TESTFLAGS='-file panedwindow.test -match "Panedwindow-1.1 Panedwindow-2.5"'
...
==== Panedwindow-2.5 configuration options, -orient FAILED
==== Contents of test case:

            .pw configure $option [lindex $test 1]
            lindex [.pw configure $option] 4

---- Test generated error; Return code was: 1
---- Return code should have been one of: 0 2
---- errorInfo: too many nested evaluations (infinite loop?)
    while executing
"destroy .pw.sash1"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 destroy .pw.sash1"
    invoked from within
...
"destroy .pw.sash1"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 destroy .pw.sash1"
    invoked from within
"destroy $itk_component($sash)"
    (object "::.pw" method "::iwidgets::Panedwindow::_makeSashes" body line 12)
    invoked from within
"_makeSashes"
    (while configuring option "-orient" for widget "::.pw")
    invoked from within
".pw configure $option [lindex $test 1]"
    ("uplevel" body line 2)
    invoked from within
"uplevel 1 $script"
---- errorCode: TCL LIMIT STACK
==== Panedwindow-2.5 FAILED