Thee DocKtor has noticed inconsistencies of scaling, orientation, attachment, etc. that vary with graphics adaptor driver versions, Windows versions, and various monitor’s manufacturers, resolutions, and sizes. Some users describe “fuzzy” graphics others just “lag” in dragging windows.
These issues have manifested when using multiple monitors whether through a USB DisplayLink, DisplayPort Alternate Mode dock, or Thunderbolt dock, dongle, or directly attached to the local graphics adaptor.
A great article on display monitor scaling is shown here. To understand what version of Windows 10 you have, see the wiki here. A Microsoft article titled, “Windows scaling Issues for high DPI devices” shows known issues here.
For possible fixes to the issue of “fuzzy” external display monitor(s), try setting the local monitor scaling to 100%, even if something different is recommended by Windows. Alternatively consider third party solutions like the one shown here.
For fixes to the issue of “lag” try the different settings for “Adjust for best performance” or “Adjust for best appearance” that fit your preferences. See the article here for more information.
With Targus Universal Docking Stations based on the DisplayLink Technology for USB display monitors in Windows 7 always enable AERO Glass.
If you are certain that the issue is with the dock, please post here and/or contact Targus to diagnose.