[Gamerkid7]

I figured that was how they were pushing the dialog, but I still can't seem to find it in any of the controls lists.

Here's the list of controls of GUIContainer:
GraalControl (GuiGraalCtrl)
MainMenuGui2D (GuiControl)
DownloadProgress_Window (GuiWindowCtrl)
ShopGlobal_Window (GuiWindowCtrl)
ShopGlobal_MessageBox (GuiWindowCtrl)
ShopGlobal_TradeQuery (GuiWindowCtrl)
PaymentOptions_Window (GuiWindowCtrl)
ShopGlobal_AccountWindow (GuiWindowCtrl)
Serverlist_ProtectQuery_Window (GuiWindowCtrl)
Serverlist_TaskBar (GuiTaskbar)
Serverlist_Taskbar_Menu (GuiStartMenuCtrl)
F2LogWindow_Window (GuiWindowCtrl)

And GraalControl:
ChatBar (GuiTextEditCtrl)
Observer_TextBackground (GuiControl)
DownloadProgress_GameFade (GuiControl)
IRC_Test_UpdateWindow (GuiWindowCtrl)
ChatBar_ToggleTaskBarButton (GuiButtonCtrl)
StartConnectMessage (GuiWindowCtrl)
ScriptedRCWindow (GuiWindowCtrl)
Serverlist_Panel (GuiControl)

None of which seem blatantly obvious to me to contain the F5 Load Level GUI