There are several options to start a new instance of UltraEdit.

There are three configuration settings at Advanced - Settings or Configuration - Application layout - Miscellaneous which controls UltraEdit instance handling on starting uedit32.exe or uedit64.exe or using the 32-bit or 64-bit UltraEdit shell extension DLL:

1. Files selected in Explorer will open in a new single instance whereby Explorer means in real any application which lets the user open files via UltraEdit shell extension.
2. Allow multiple instances
3. Maintain separate process for each file opened from external application

The help page opened on clicking on button Help or pressing key F1 in this configuration dialog explains those three settings.

On command line or in a shortcut file (*.lnk) it is possible to use /fni to force starting a new instance or /fno to force usage of an old (already running) instance independent on configuration setting Allow multiple instances. This parameter must be the first argument after executable on usage. For more information about command line arguments see help page with title Command Line Parameters which can be opened via help tab Index.

On using ribbon mode it is possible to click on ribbon tab Window in last ribbon group Application on last item New instance to open a new instance of UltraEdit. On using toolbar/menu mode with contemporary menus the command New instance can be found in menu Window. And on using toolbar/menu mode with traditional menus the menu Advanced has the menu item Open new instance of UltraEdit.

It is possible to click with primary (left) pointing device (mouse) button on a file tab, hold primary button, drag the pointer (cursor) being now a symbol with a text sheet + pointer outside main application window of UltraEdit and drop the file tab there with leaving mouse button. The area on which the file tab is dropped can be even the Windows task bar area. This results in starting a new instance of UltraEdit with moving the clicked file tab into this new instance. This method to drag and drop a file in an opened instance of UltraEdit to another opened instance or to a new instance is explained on help page File tabs command (Layout tab) which can be opened via File Tabs list item on help tab Index.

Last I want to mention also the configuration setting Store windows/menu/toolbars placements and configurations for multiple instances of application at Advanced - Settings or Configuration - Application layout - Advanced. The usage of using a per instance workspace configuration is useful for example on first instance should be always opened maximized on primary screen and second instance should be always opened maximized on secondary screen.