Mathematica's unified symbolic architecture allows arbitrary extensibility in the output and input of notation.
$ControlActiveSetting is a symbol whose value is True if it is evaluated while a control is active, or in certain other previewing situations.
NotebookEventActions is a notebook option that gives a list of actions to perform when specified events occur in connection with the notebook.
GUILoad[src] loads an interface definition and returns immediately with a GUIObject result.GUILoad[src, args] passes arguments to the interface definition.
FindLibrary[lib] finds a dynamic library that can be loaded by LibraryFunctionLoad.
LibraryFunctionInformation[fun] returns information about a LibraryFunction.
WindowTitle is an option that specifies the title to give for a window.
Mathematica provides a full range of control objects, all specified in convenient symbolic form. Manipulate uses many of these objects automatically; you can also use them ...
GetJavaException -- get the exception object thrown in the most recent Java call, JavaThrow -- throw a Java exception, $JavaExceptionHandler -- how Java exceptions are ...