Lua Console Right-click crash(It looks like the same bug happened in several places)

1. After opening the Lua Console window, first right-click in the message window under the “Output” tab, then immediately right-click in the list on the left; an error occurs.
2. When open the Cheat window, click any menu item, and then immediately right-click the list below, an error occurs.
   有关调用实时(JIT)调试而不是此对话框的详细信息，
   请参见此消息的结尾。

************** 异常文本 **************
System.NullReferenceException: 未将对象引用设置到对象的实例。
在 BizHawk.Client.EmuHawk.InputRoll.CalculatePointedCell(Int32 x, Int32 y) 位置 /src/BizHawk.Client.EmuHawk/CustomControls/InputRoll/InputRoll.cs:行号 1941
在 BizHawk.Client.EmuHawk.InputRoll.OnMouseMove(MouseEventArgs e) 位置 /src/BizHawk.Client.EmuHawk/CustomControls/InputRoll/InputRoll.cs:行号 1070
在 BizHawk.Client.EmuHawk.InputRoll.OnMouseDown(MouseEventArgs e) 位置 /src/BizHawk.Client.EmuHawk/CustomControls/InputRoll/InputRoll.cs:行号 1187
在 System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
在 System.Windows.Forms.Control.WndProc(Message& m)
在 System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Start with BizHawk.Client.EmuHawk/CustomControls/InputRoll/InputRoll.cs, especially CalculatePointedCell at line 1941 and the mouse handlers at lines 1070 and 1187. Reproduce the right-click sequences in the Lua Console and Cheat window, then trace which state is null. Done means both workflows no longer raise the reported NullReferenceException.