Edit
Undo 
UModel has an unlimited number of "Undo" steps that you can use to retrace your modeling steps.
Redo 
The redo command allows you to redo previously undone commands. You can step backward and forward through the undo history using both these commands.
Cut/Copy/Paste/Delete
These are the standard Windows text editing commands. You can use them not only for text but also for modeling elements, see Renaming, Moving, and Copying Elements.
Paste in Diagram only
Adds a "link" (or "view") of the copied element to the current diagram but not to the Model Tree, see Renaming, Moving, and Copying Elements.
Delete from Diagram only
Deletes the selected modeling elements from the currently active diagram. The deleted elements are not deleted from the modeling project and are available in the Model Tree tab. Note that this option is not available to delete properties or operations from a class, they can be selected and deleted there directly.
Select all
Select all modeling elements of the currently active diagram. Equivalent to the Ctrl+A shortcut.
Find
Allows you to search for specific text in the current window, see Finding and Replacing Text.
Find Next 
F3
Searches for the next occurrence of the same search string in the currently active window.
Find Previous (Shift+F3)
Searches for the previous occurrence of the same search string in the currently active tab or diagram.
Replace
Allows you to search and replace any modelling elements in the project, see Finding and Replacing Text.
Copy as Bitmap
Copies the currently active diagram to clipboard, from where you can paste it into the application of your choice.
Copy Selection as Bitmap
Copies the currently selected diagram elements to the clipboard from where you can paste them into the application of your choice.