Dialog windows (or dialog boxes) are special notebook windows of the Mathematica front end. As such, they can be edited and called for programmatically, just like any other expression. Dialogs can be created with the
CreateDialog function, which is a specialized version of
CreateWindow[DocumentNotebook[...]], with special options. More specialized dialogs for certain tasks are available using the functions:
SystemDialogInput. The function
DialogNotebook represents a dialog notebook in Mathematica.
Questions dealing with general notebook editing via the front end should use the tag notebooks or front-end. Questions about palette notebooks should use the tag palettes. Questions about the system dialog windows produced by the OS should use the tag system or the specific OS tag (e.g. windows or macosx).