Clicking on a test title crash about snapshots

[orta]

Application Specific Information:
Sending tappedButton: to <ORSnapshotDiffs: 0x7f9abd1a8b40> from <NSButton: 0x7f9a7d8ea9a0>
ProductBuildVersion: 7C1002
UNCAUGHT EXCEPTION (NSRangeException): *** -[__NSArray0 objectAtIndex:]: index 18446744073709551615 beyond bounds for empty NSArray
UserInfo: (null)
Hints: 
  0: Sending tappedButton: to <ORSnapshotDiffs: 0x7f9abd1a8b40> from <NSButton: 0x7f9a7d8ea9a0>
Backtrace:
  0  0x00007fff9ac0faca __exceptionPreprocess (in CoreFoundation)
  1  0x00000001043cbb07 DVTFailureHintExceptionPreprocessor (in DVTFoundation)
  2  0x00007fff9860e73c objc_exception_throw (in libobjc.A.dylib)
  3  0x00007fff9aba61f5 -[__NSArray0 objectAtIndex:] (in CoreFoundation)
  4  0x000000011174579f -[ORPopoverTableDataSource objectForRow:] at /Users/orta/Library/Application Support/Alcatraz/Plug-ins/Snapshots/SnapshotDiffs/ORPopoverTableDataSource.m:90 (in Snapshots)
  5  0x000000011174301a -[ORPopoverController tableViewSelectionDidChange:] at /Users/orta/Library/Application Support/Alcatraz/Plug-ins/Snapshots/SnapshotDiffs/ORPopoverController.m:84 (in Snapshots)
  6  0x0000000111742daa -[ORPopoverController awakeFromNib] at /Users/orta/Library/Application Support/Alcatraz/Plug-ins/Snapshots/SnapshotDiffs/ORPopoverController.m:58 (in Snapshots)
  7  0x00007fff8d63ef20 -[NSIBObjectData nibInstantiateWithOwner:options:topLevelObjects:] (in AppKit)
  8  0x00007fff8d80280a -[NSNib _instantiateNibWithExternalNameTable:options:] (in AppKit)
  9  0x00007fff8d80245a -[NSNib _instantiateWithOwner:options:topLevelObjects:] (in AppKit)
 10  0x00007fff8d801953 -[NSViewController loadView] (in AppKit)
 11  0x00007fff8d788d08 -[NSViewController _loadViewIfRequired] (in AppKit)
 12  0x00007fff8d788c73 -[NSViewController view] (in AppKit)
 13  0x00007fff8d890627 -[NSPopover showRelativeToRect:ofView:preferredEdge:] (in AppKit)
 14  0x000000011174985a -[ORSnapshotDiffs tappedButton:] at /Users/orta/Library/Application Support/Alcatraz/Plug-ins/Snapshots/SnapshotDiffs/ORSnapshotDiffs.m:94 (in Snapshots)
 15  0x00007fff9812c07a _os_activity_initiate (in libsystem_trace.dylib)
 16  0x00007fff8d84c51d -[NSApplication sendAction:to:from:] (in AppKit)