The task requires browsing or comparing many types of data before finalizing a task.

Modeless Window

The task requires browsing or comparing many instances of the same type of data before finalizing a task.

Modeless Multiple-Instance Window

Each discrete activity performed by a window's procedure must be completed before the user moves on to the next activity (guides the user through the work and helps to maintain data consistency).

Modal Window
or
Modeless Single-Instance Window

User actions need to be confirmed because there is a chance of an action being performed for the wrong object.
This can be set as a development standard, for example, use a confirmation dialog box for all deletions.

Modal dialog box

Messages are presented to the user by exit states.

Modal Dialog Box