Seriously, this is driving me crazy. When using the Pulse Secure VPN client with Windows 10 and 2 factor authentication, the dialog where you enter the PIN code IS NOT MODAL. This appears to have been the case with the password dialog also. Despite having the Pulse Secure dialog on top of everything with the blinking text cursor in it, when I typed in my password it instead ended up in the Skype window forcing me to change that on several places.
PLEASE, fix this problem and make the password/PIN dialog windows MODAL!