What are the other Mono dependencies besides mono-runtime and libmono-system-windows-forms4.0-cil required to run C# Windows Forms applications on Ubuntu Linux 16.04? Does the answer to our question depend on the C# source code for our Windows Forms applications? For example, hellboy81  wrote on gitter im mono, Feb 10 01:46.I have Issue with WinForms's TreeView control in Mono under Ubuntu 64  Bit 15.10 (Unity) items are not selectable and selection is not  visibleDoes there exist a package update or new package to fix this problem?I believe the other Mono dependency, GTK# 2.0 is found by using: strace mono ./Simple.exe If I add the line:using GTK;to Simple.cs and compile:mcs -r:System.Windows.Forms.dll -r:System.Drawing.dll -pkg:gtk-sharp-2.0 Simple.cs -out:Simple.exe The compiler output is:Package gtk-sharp-2.0 was not found in the pkg-config search path. Perhaps you should add the directory containing `gtk-sharp-2.0.pc' to the PKG_CONFIG_PATH environment variable No package 'gtk-sharp-2.0' found.May I ask if gtk-sharp-2.0 is a dependency required for System.Windows.Forms and whether there are any other Mono dependencies? Our architect does not want to consider libgtk2.0-cil-dev as an example of a missing Mono dependency. Instead, he wants to find out what dependencies do we need other than mono-runtime and libmono-system-windows-forms4.0-cil for List Box, ComboBox, EditBox, buttons, etc.. Do List Box, ComboBox, EditBox, buttons, etc.. require additional Mono dependencies? 
What are all the Mono dependencies required to run all types of C# Windows Forms applications?
ubuntu;mono
The problem here is that your Mono applications are, just like any other source code, outside of the package management system's control.  Therefore you need to work out yourself which packages you need to install - nothing will tell you.You have a few options and the simplest of those is to read the developer's documentation.Failing that, you can (as you have started) run strace and see what's missing.  The problem then is working out which package that file belongs to.  In Ubuntu, you can use apt-file as follows:Install and configure it:$ sudo apt-get install apt-file$ apt-file updateThen find the package with:$ apt-file search gtk-sharp-2.0.pcand it'll tell you that you need to install libgtk2.0-cil-dev for this file.Next run the Mono application again and if need be, strace and apt-file will help you find the missing files.