If you publish an RemoteApp the Ressources tag switch from RemoteDesktop to RemoteApp. That means your host is either a full classice RemoteDesktop host or an RemoteApp host. Domain Admins can enter the host via full RemoteDesktop anyways.
mstsc /admin /v:YOUR-RDSH
1. Go to TS and do: query session to get users SESSION_ID 2. Go to another machine and do mstsc /v:COMPUTERNAME_OR_IP /shadow:SESSION_ID /control
Its a display driver problem, Do gpedit.msc: Local Computer Policy Computer Configuration Administrative Templates Windows Components Remote Desktop Service Remote Desktop Session Host Remote Session Environment Use WDDM graphics display driver for Remote Desktop Connections to DISABLED Credits: https://answers.microsoft.com/en-us/windows/forum/all/dwmexe-high-cpu-one-core-on-target-system-after/dbce0938-60c5-4051-81ef-468e51d743ab
Do you have keymap problems connecting from linux to windows? Maybe rdesktop -k KEYMAP cannot find the keymap file it is searching for. Check /usr/share for rdesktop/keymaps and copy this stuff to ~/.rdesktop/keymaps/