after pushing some changes via filezilla (SFTP) I can't commit the changes on the dashboard of pantheon as the commit button is not enabled. I don't know if I am missing something
David from Pantheon here. The fastest place to get help with questions like this is support chat from your site dashboard. They can take a look at your site and give you direct support.
The only time I see the commit button disabled is when the dashboard hasn't detected any code changes. You should be able to click on the changed files to see a diff.
Occasionally I'll need to re-save my code to trigger a re-upload in my SFTP app, then refresh the dashboard. Sometimes it takes 30 seconds or so to show up, and other times a refresh is necessary.
If you need additional help, you should check out our weekly Office Hours and Power Users Slack (where you can catch me directly).