Hello Sr./Ms., Most everyone in my laboratory has access to UCSF Chimera and can use it with no issues. However, one new person has had trouble selecting atoms. Specifically, neither CTRL + Left Click nor CTRL + SHIFT + Left Click appear to work on selecting atoms in a molecular geometry, even though their computer can run the program. They can translate, rotate, and zoom in-and-out of the geometry, and they can use actions such as "Select All" . However, they cannot deselect individual atoms once the entire geometry is selected, and they can only CTRL + Left Click outside the geometry to deselect the entire geometry. Additionally, drag-clicking does not appear to work. CTRL + Click is a fundamental feature that our group uses, especially since we use Chimera for journal figures. Are there any suggestions on how to troubleshoot the issue with selecting atoms? For reference, their computer runs Windows 10 and operates on a x64 bit system. Any help is appreciated, Luke