PGADMIN4's Query Tool will run only the highlighted SQL when a section of the SQL window is highlighted. In the Windows operating system, this same window allows the highlighting of non-contiguous areas using ctrl-click&drag on the mouse, but executing such multi-region highlighted code fails because only the bottom-most highlighted region is executed.
Note that this could be VERY useful when you have coded a CTE (common table expression), as this code is at the top of the SQL and its utilization may occur significantly below its definition.