I noticed the following Lua-Error that apparently occured while i did a LFG-Dungeon (Outland) on an lowlevel alt. Nothing major, probably not even worth a fix, but you probably like bugfree code so hit it hard and with fire. Occures on MDT v2.1.9.2 (Twitch client)

13x ...aceMethodDungeonTools\MethodDungeonTools-2.1.9.2.lua:148: attempt to index field 'main_frame' (a nil value)
...aceMethodDungeonTools\MethodDungeonTools-2.1.9.2.lua:148: in function <...aceMethodDungeonTools\MethodDungeonTools.lua:146>
(tail call): ?

Locals:
self = {
0 =
}
addon = nil
inGroup = true
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "attempt to index field 'main_frame' (a nil value)"
MethodDungeonTools =

{
DungeonEnemies_UpdateSelected = defined @MethodDungeonTools\DungeonEnemies.lua:406
PresetObjectStepBack = defined @MethodDungeonTools\MethodDungeonTools.lua:2412
CreateTutorialButton = defined @MethodDungeonTools\MethodDungeonTools.lua:2212
GetCurrentPull = defined @MethodDungeonTools\MethodDungeonTools.lua:1233
CreateDungeonSelectDropdown = defined @MethodDungeonTools\MethodDungeonTools.lua:1435
dungeonMaps = {
}
MakePresetCreationFrame = defined @MethodDungeonTools\MethodDungeonTools.lua:1708
DungeonEnemies_UpdateInfested = defined @MethodDungeonTools\DungeonEnemies.lua:471
ReleaseAllActiveTextures = defined @MethodDungeonTools\toolbar.lua:296
SendToGroup = defined @MethodDungeonTools\Transmission.lua:231
IsPresetTeeming = defined @MethodDungeonTools\MethodDungeonTools.lua:1258
HideInterface = defined @MethodDungeonTools\MethodDungeonTools.lua:476
DrawAllPresetObjects = defined @MethodDungeonTools\MethodDungeonTools.lua:2338
dungeonBosses = {
}
GetCurrentAffixWeek = defined @MethodDungeonTools\MethodDungeonTools.lua:2466
DeletePull = defined @MethodDungeonTools\MethodDungeonTools.lua:2036
RestoreScrollframeScripts = defined @MethodDungeonTools\toolbar.lua:431
PresetObjectStepForward = defined @MethodDungeonTools\MethodDungeonTools.lua:2432
ADDON_LOADED = defined @MethodDungeonTools\MethodDungeonTools.lua:117
UpdateDungeonEnemies = defined @MethodDungeonTools\MethodDungeonTools.lua:1363
UpdateProgressbar = defined @MethodDungeonTools\MethodDungeonTools.lua:1007
dungeonEnemies = {
}
POI_CreateFramePools = defined @MethodDungeonTools\Pointsofinterest.lua:8
CreateDevPanel = defined @MethodDungeonTools\devpanel.lua:97
MakePullSelectionButtons = defined @MethodDungeonTools\MethodDungeonTools.lua:1803
StorePresetObject = defined @MethodDungeonTools\MethodDungeonTools.lua:2299
StartEraserDrawing = defined @MethodDungeonTools\toolbar.lua:736
TableToString = defined @MethodDungeonTools\Transmission.lua:96
ShowEnemyInfoFrame = defined @MethodDungeonTools\EnemyInfo.lua:126
GetDungeonName = defined @MethodDungeonTools\MethodDungeonTools.lua:197
UpdatePullTooltip = defined @MethodDungeonTools\MethodDungeonTools.lua:1096
GetHighestFrameLevelAtCursor = defined @MethodDungeonTools\toolbar.lua:455
DisplayBlipTooltip = defined @MethodDungeonTools\DungeonEnemies.lua:200
ClearPull = defined @MethodDungeonTools\MethodDungeonTools.lua:2012
StringToTable = defined @MethodDungeonTools\Transmission.lua:106
SkinProgressBar = defined @MethodDungeonTools\MethodDungeonTools.lua:509
MakeRenameFrame = defined @MethodDungeonTools\MethodDungeonTools.lua:2055
StartMovingDrawing = defined @MethodDungeonTools\toolbar.lua:680
DisableBrushPreview = defined @MethodDungeonTools\toolbar.lua:340
initToolbar = defined @MethodDungeonTools\toolbar.lua:17
POI_UpdateA