My World 3 for Windows TM
You can adjust the size of the popup window by double clicking on the backdrop to open the Frame Properties dialogue box then editing the numbers in the width and height boxes.
Drag the popup window to the position where you want it to appear.
You must set the frametype of the popup backdrop, as you did for the main screen.
A suitable frametype is PopupTitleOnly, which removes the window furniture from the popup's title bar.
Doubleclick on the popup's backdrop, then choose from the Frame Types menu.
You now need to make the popup open on command. To do this, you will need to add a script file to the main screen.
You have already seen that frames can be set to Copiable, Moveable etc.
This process is controlled by a script language.
The Frame Types menu is a set of pre-defined frame types stored in a global resources directory inside My World which cannot be altered (if you did so, screens made by other authors would be affected).
However, you can copy these script files to a screen's local directory and edit it.
You can see the range of available frame type scripts by selecting Mwb files from the View menu.
To open a popup when the main screen opens, you can set the main screen's backdrop to Dropzone1.mwb.
Like all .mwb script files, this is a plain text file. You can open it in any text editor, such as Notepad.
Please take a moment to do this, and to look at the structure of the file.