Fix https://github.com/twentyhq/twenty/issues/17507
The canvas layout mode is expected to render a single widget.
Previously, we threw an error when trying to render a canvas layout with
no widgets at all. This worked fine when we immediately rendered a
widget that used a single-widget canvas layout.
However, the active tab ID is shared across all page layouts with the
same ID, which doesn’t work well with conditional display. The available
tabs may depend on conditions such as the device displaying the page.
For example, when displaying a Note on the show page, the Note widget
appears on a separate tab. On mobile and in the side panel, however, it
is moved to the Home tab.
After that, if the user opens a Note in the side panel, the default
active tab might be the Note tab, which uses a _canvas_ layout mode and
would have no widgets at all when rendered in the side panel. This leads
to the error mentioned above.
The simple workaround is to wait one tick. An `Effect` component then
detects that the active tab doesn’t exist in the list of allowed tabs
and switches to another tab by default.
This feels more like a workaround than a proper solution, but I prefer
to fix it this way for now. We can later revisit this and design a
better separation for the selected tab ID state.
## Before
https://github.com/user-attachments/assets/500e332c-1623-48e5-b69b-5a4fa4e5e28d
## After
https://github.com/user-attachments/assets/b39dcf96-1852-42e4-a8cc-a79bf9036579
