FX 2.45 build 19

2.45.1901 (also known as CBASIC245beta19) is the 14th build for FX 2.45, released on May 20, 2020.

Additions

 * Extended Screen command.
 * Extended System command.
 * Executing System(-1) in fx-9750GIII returns 6.

Changes

 * Changed the specification of the ReadGraph/WriteGraph/DotGet/DotPut command to work on the current VRAM.
 * Updated System command sample program to support fx-9750GIII.

Fixes

 * Fixed the bug that and   did not work after escaping from Try-structured command with Break command.