vkconfig: Selecting an application from the application dialog is clunky

[richard-lunarg]

Under macOS, bringing up the "Applications to override Vulkan Layers" dialog while "Apply only to selected list of Vulkan applications", does not allow you to select an application. Checkboxes work, but you cannot change to a new application in the list. This does not occur when the checkboxes are not present, and this does not occur under Windows.