Hello,
So, it seems you have buy a site template with iCagenda included...
Note: i have NO partnership with any template providers !
You should contact your site template provider, as they are responsible for what they do. I can't give support for not officially downloaded and installed iCagenda version, as i can't know what was done by other developer.
All the tabs are generated by site template, maybe with overrides for iCagenda views.
For now, the only think i can tell you is that iCagenda version installed is 3.6.4, which one is an old version (latest is 3.6.10, and soon released 3.6.11).
So for all display issue, contact your site template support, as all the design was done by them (which is allowed by the flexibility of iCagenda so that's not bad, but i can't fix myself their code
)
Hope this helps you ?
Best regards,
Cyril