Feature request: Support double click, shift click on TransferList

[HaveSpacesuit]

I'm replacing our custom build transfer list with the iTwin TransferList. A couple features are missing in the iTwin implementation, and it would be great if we could see them added:

• Double click a list item -> transfers to the opposite list
• Shift+click within a list -> selects all list items between last selected and where Shift+click was applied (same as the Shift+click in the table)

[mayank99]

I don't think we would add the double-click functionality within iTwinUI, because it feels too arbitrary (you are still free to add it in your product if you explain it well to your users). However, shift+click makes sense to add, as it is fairly common and more intuitive.

Since we already have shift+click implemented in Table, maybe it would also make sense to abstract that logic into a common helper function that can be used in both places? Might be difficult though, as it relies on implementation details of the Table component. The code can be found here:

iTwinUI/packages/itwinui-react/src/core/Table/actionHandlers/selectHandler.ts

Line 123 in d1af8d0

export const onShiftSelectHandler = <T extends Record<string, unknown>>(

That being said, we don't currently have the bandwidth to work on this. Maybe you'd like to contribute this feature?