ToolBar control issue on Linux

Hi!

ToolBar control does not work on Ubuntu 20.04. I received the following exception in ToolBar’s constructor when running on Ubuntu. Compiling and running on Windows were without problems. We are using WiseJ 3.1.5 and have Mono 6.12.0.182. See below for the call stack.

Please advise.

Thanks,
Yaroslav

Exception:

System.DllNotFoundException: Unable to load shared library ‘user32.dll’ or one of its dependencies. In order to help diagnose loading problems, consider setting the LD_DEBUG environment variable: libuser32.dll: cannot open shared object file: No such file or directory at Wisej.Base.WinSDK.GetDC(IntPtr hWnd)
at Wisej.Base.TextUtils.get_DeviceContext()
at Wisej.Base.TextUtils.GetFontHeight(Font font)
at Wisej.Web.Control.get_FontHeight()
at Wisej.Web.Control.GetPreferredSizeCore(Size proposedSize)
at Wisej.Web.ToolBar.get_DefaultSize()
at System.Windows.Forms.Control..ctor(Boolean autoInstallSyncContext)
at System.Windows.Forms.Control..ctor()
at System.Windows.Forms.ScrollableControl..ctor()
at Wisej.Base.ControlBase..ctor()
at Wisej.Web.Control..ctor()
at Wisej.Web.ToolBar..ctor()
at ToolbarError.MainWindow.InitializeComponent() in /home/user/Documents/projects/ToolbarError/ToolbarError/MainWindow.Designer.cs:line 34
at ToolbarError.MainWindow..ctor() in /home/user/Documents/projects/ToolbarError/ToolbarError/MainWindow.cs:line 11
at ToolbarError.Program.Main() in /home/user/Documents/projects/ToolbarError/ToolbarError/Program.cs:line 13