Keyboard nav: duplicating blocks via the context menu should put you in move mode

[srietkerk]

When a user duplicates a block, I think the likelihood that they would want to move that block is pretty high. However, with keyboard navigation, the block that you just created from duplication is not in move mode. This feels a bit jarring because when you select a block from the toolbox, it is in move mode by default. My suggestion would be to have duplicated blocks in move mode by default, just as we have blocks that a user takes from the toolbox.

To Reproduce
Steps to reproduce the behavior:

1. Go to beta
2. Open a new project
3. Add some blocks to your project
4. Open the context menu on a block with keyboard navigation (control+enter)
5. Select duplicate with keyboard navigation
6. See that the duplicated block is not in move mode

Desktop (please complete the following information):

• OS: Windows and Mac
• Browser Edge and Chrome

[microbit-matt-hillsdon]

This (and the related case of copy/paste) was considered and in the end rejected in the Blockly keyboard navigation plugin design as used in MakeCode 2025 and the same behaviour has been carried forward as the implementation moved to Blockly core.

Old issues with debate/discussion for context:
RaspberryPiFoundation/blockly-keyboard-experimentation#480 (most discussion here)
RaspberryPiFoundation/blockly-keyboard-experimentation#478