Global Hot Key to Restore KeePass Window
To quickly switch back from an application to KeePass, you can use the global hot key that restores the KeePass main window.
If you have multiple instances of KeePass running, pressing the global hot key will restore the first instance that has been started.
The global hot key is Ctrl+Alt+K.
KeePass 1.x OnlyThe hot key cannot be changed, however it can be disabled in the advanced options.
KeePass 2.x OnlyThe hot key can freely be changed to a different key combination (or disabled) in the 'Options' dialog, tab page 'Integration'.
Limit to Single Instance Option
If you enable the 'Limit to Single Instance' option, at most one KeePass instance can be running at a time. If you try to start a second KeePass instance, it is immediately terminated, and the first instance is brought to the foreground.
KeePass 1.x OnlyIf the second instance was started using a command line specifying a database to open, and the first instance doesn't have a sub-dialog open, the first instance attempts to close the current database. If this attempt is successful (or if no database was open in the first place), the first instance opens the database specified by the second instance's command line, using any
KeePass 2.x OnlyKeePass 2.x can open multiple databases in one instance/window (a tab bar appears, which allows you to conveniently switch between the databases).
When multiple databases are opened in one instance and you press the global auto-type hot key, auto-type searches in all opened databases for matching entries. Note that only exactly one KeePass instance can register the global hot key; so when you disable the single instance option and open databases in different instances, only the first instance searches for matching entries when global auto-type is invoked, not the others.