We are aware that some users are having trouble when selecting text on windows. The reason stems from Windows’ Desktop Zoom feature which allows a user to view the desktop at different zoom levels. However, Shift’s GUI is not optimized to work at very large settings. If you are experiencing this issue, please follow the following steps to troubleshoot:
In Control Panel → Appearance → Display, select a zoom level of 100% or 125%.
For Windows 8.1 users there is an additional option to apply one scaling level for all connected displays. Make sure this is checked: