Click menu within the same Main window


#1

Am developing this new desktop app that will serve as an archive or database for keeping information of workers.

  1. First question
    But from my menu
    When I click on any of them, it pops up to a new window instead of working within the same main window. What should I do pls?

  2. Database for my app
    Any suggestions ?
    Since I will create a table to contain details like “Name , Phone, department , date started etc.

  3. How do I make my app fast cos it seems it’s slow to me .

Thank you.