Custom block view mode should only display if there's more than one

Hiding the possibility makes sense.

We also discussed if there should be a link to manage view modes (admin/structure/display-modes/view) or create a new view mode (admin/structure/display-modes/view/add/block_content). This could be done as an improvement, but would need to check if the current user has the permission to edit view modes.

taking a stab at this

here's a patch that will hide the select element if no more than 1 view modes exist. didn't implement the configure link

thanks chris_h! could you also link to the follow-up issue once created?

We can (and should) add a test for this.

phew, it took me a while to figure out that after

    $this->drupalPostForm('block/add/basic', $edit, t('Save'));

we are automatically on the block instance form where we can check the view_mode settings.

i decided to add a second testBlockContentCreationMultipleViewModes test function, because the inter-dependencies of view modes and the test cases just got a bit too crazy from me when i tried to integrate the multiple check into the existing one :)

thanks for reviewing!

sorry now the correct patch version with interdiff

Applies, works as expected. Should make the form simpler by removing a field not always of concern to a user, because there is one option.

+1 RTBC - thanks

Added beta-eval and used the issue summary template

Thanks for adding the test. Committed 7e57c75 and pushed to 8.0.x. Thanks!

Thanks for adding the beta evaluation to the issue summary.