Breakpoints
Breakpoints are source code markers used to trigger actions during a debugging session.
Breakpoint types
MPS lets you create breakpoints of several types. Each breakpoint type supported by MPS addresses different debugging needs and has its own individual settings.
MPS enables you to set the following types of breakpoints:
Temporary line breakpoint
These breakpoints are assigned to lines of source code and are used to target a particular section for debugging. When hit, such breakpoints are immediately removed.
Exception breakpoint
MPS provides exception breakpoints for and JavaScript.
Exception breakpoints are triggered when the specified exception is thrown. Unlike the line breakpoints, which require specific source references, exception breakpoints apply globally to the exception condition, rather than to a particular code reference.
Breakpoints icons and statuses
When a breakpoint is set, the editor displays a breakpoint icon in the gutter area to the left of the affected source code. A breakpoint icon denotes status of a breakpoint, and provides useful information about its type, location, and action.
The icons serve as convenient shortcuts for managing breakpoints. Clicking an icon removes the breakpoint. Successive use of Alt ⌘ - click on an icon toggles its state between enabled and disabled. The settings of a breakpoint are shown in a tooltip when a mouse pointer hovers over a breakpoint icon in the gutter area of the editor.
The table below summarizes the possible breakpoint states:
When the button 
is pressed in the toolbar of the Debug tool window, all the breakpoints in a project are muted, and their icons become grey: 
.