I can't change the active page of notebook & page control in following case:

1) I use Delphi 5.

2) My program has two output file:
Main.exe - contains a main form in it.
AddOn.bpl - contains a TNotebook componient (has multiple pages) on a form. Also, a button is created on the form for changing page of notebook.

3) The main program "Main.exe" loads the package file "AddOn.bpl".

4) After the package is loaded, the form contains notebook in AddOn.bpl is dock to the main form in Main.exe. (by ManualDock function).

5) I click the button on the form to change notebook page, the page index could be changed to the second page, but the screen still show first page of note book.

6) I try to not use the load package method, instead of the main form directly uses the form in the package. There is no problem occurs.