Restore previously open project and pages when starting

Try clicking "Auto Save Project Options" on the first page of the Tools/Options dialog.

From the help file:

Autosaves or updates the project desktop file (.dsk file extension) when you close the project or exit the product.

The .dsk file records your current settings for:

• Desktop layout
• Breakpoints
• Watch items
• Files currently open in the IDE

When you reopen the project later, the .dsk file is read, and your desktop layout, your breakpoints, and your watches are all restored. Also, all files that were opened when the project was closed are opened again, regardless of whether they are used by the project.

As of 10.3 Rio, you can find this option in Tools > Options > IDE > Saving and Desktop under the Autosave section,