Unable to resize windows in an MSTSC RDP Proxy session

Products

• CA Privileged Access Manager (PAM)

Issue/Introduction

For specific Windows servers, users have problems resizing the windows within the MSTSC session. When they move the mouse over an edge or corner of a window within the RDP session, the mouse pointer does not change, which makes it look like window resizing is not possible at all. However, if they left-click the mouse while it's right at an edge, or on a corner, the window in fact will resize, the problem is just that the mouse pointer does not change to the expected double-arrow.

This is not observed with sessions using the build-in RDP access method.

Environment

PAM versions 4.2.3 and lower.

There is a residual problem that affects all PAM versions, see details below.

Cause

The problem affects all RDP Proxy sessions, if mouse option "Enable pointer shadow" is checked on the RDP server.

 With this option enabled, the remote server only sends the system default pointer. All the other pointers such as the window resizing pointers are not sent to the client. With no specific pointer sent, the PAM RDP Proxy has no choice but to keep showing the default pointer at the edges and corners of the windows.

Resolution

The conflict with mouse option "Enable pointer shadow" is resolved in the 4.3 release. In 4.3+ the RDP Proxy disables the option while establishing the connection. The PAM RDP client (RDP access method) has been doing this since early 3.X releases.

Additional Information

There is a residual problem affecting high resolution displays with a Scale setting of more than 100%. On such displays the problem may persist even with the fix, and even when option "Enable pointer shadow" is disabled. A workaround would be to change the Scale setting to 100%. On some displays a setting of 125% may work. This is a generic problem that affects non-GFX RDP clients like the PAM RDP Proxy. The RDP server should handle the mouse pointer change, but it doesn't notify non-GFX clients of the pointer change. This may be fixed by Microsoft in the future. PAM cannot change to GFX clients, because that would break session recording. The PAM client RDP access method does not send scaling information to the RDP server and should not have this problem.

Also, when enabling the "Enable pointer shadow" option explicitly within the established RDP Proxy session, the problem will come back. This is the case for the PAM client RDP access method as well. Don't enable this option during an RDP session launched from PAM.