Collabora Office Calc on Android tablet: Cannot Paste

As I don’t know if this forum only takes issues on Collabora Onlne:
I do have two Android tablets (Galaxy SII and Galaxy S7+) The NotebookBar is shown as UI and it does not offer any functionality to Copy and paste content in the spreadsheet. Is his a known bug or am I doing something wrong? On a phone a different UI is shown, that has Copy & paste availbale…
Thanks for any help,