To toggle a breakpoint on an element on the Design board:
Right-click the element and choose Toggle Breakpoint from the context menu to add or remove the breakpoint.
As a result of adding a breakpoint, a (blue circle) icon is added next to the element, and the breakpoint is added to the Breakpoints View.
Removing a breakpoint removes the breakpoint icon from both the Design board and the Breakpoints View.
Note
You can also remove a breakpoint in the Breakpoints View by selecting the breakpoint and either pressing the DELETE key, or by choosing Remove/Remove All from the context menu of the breakpoint.