Question

the extension of forms created in visual basic​

Answer 1

Answer:

In computer programming, a Visual Basic Extension (commonly abbreviated VBX) or custom control, was the component model used in Microsoft Visual Basic versions 1.0 to 3.0. It is still supported in the 16-bit version of version 4.0, but was made obsolete by OCXs. VBX has also been supported in the first, 16-bit version of Borland Delphi.

The VBX specification was created so that developers could extend Visual Basic. Since at the time Visual Basic was an interpreted language with limited speed, VBXs, which were most often written in C or C++, provided the ability to create very powerful and efficient user interface sub-components which could be assembled into applications using Visual Basic as the glue.