Local backend implementation breaks dragging and dropping of cards (cards disappear, or get duplicated or simply do not move)

[alfredbaudisch]

The implementation from the local-backend branch breaks dragging and drop for both using the remote Elixir adapter and the local adapter.

In that implementation, it's not possible to drag and drop cards between lists anymore. And when toggling to the Elixir backend, when dragging cards and dropping on lists, they either get duplicated or removed.

Until this issue is fixed, the local backend implementation cannot be merged into master.

NOTICE: This bug is considered critical only when using the local backend branch [it breaks the main feature of the GUI implementation which is the dragging and dropping]. The original code in the master branch is fine.

How to Reproduce

• Godot 3.5.2-stable
• Get Godello from the local-backend branch
• Create a Board, 2 lists and a card in each list
• Now drag the cards around
• Now go to Settings, switch to the Elixir backend (no need to have the backend actually running)
• Create Board, 2 lists and a card in each list
• Drag cards around

DragBroken.mp4

Expected

• You should be able to drag and drop cards seamlessly between lists.
• You should be able to drag and drop cards to sort them seamlessly.

DragWorking.mp4