Steve,
There are a couple of places you could look for a resolution to this.
In the Horizon Client:
Start Horizon Client and connect to a server.
In the desktop and application selector window, right-click the remote desktop or published application and select Settings.
Select the Allow display scaling checkbox.
To save your changes, click Apply.
To close the dialog box, click OK.
In Registry or GPO DPI Synchronization:
GPO: Administrative Templates (Computer) -> VMware View Agent Configuration -> Agent Configuration -> DPI Synchronization (Enabled)
Registry on Master Image: HKLM\Software\Policies\VMware, Inc.\Vmware VDM\Configuration\DPI Sync (Set enabled 1)
I have had success with both of these options to allow the client to adjust display properly, especially with the new Retina displays.
Hope this helps.
Joe