I would like to start an external sequencer as soon as I hit a key on the MODX. All the related MIDI settings (MIDI Clock, Transport etc.) are okay. To get the MODX sending a start event to the external gear, I created an empty pattern with activated "Key On Start" option. This method actually works great so far.

Unfortunately, I must keep the Pattern page open. For example, in the Performance Home view, the sequencer does not start when I press a key. I must always be on the Pattern page. What am I doing wrong?

You are not doing anything wrong.

You can return to the Performance HOME screen once you have started the Pattern with “KEY ON START”
Your navigation while the Pattern Sequencer is running is restricted to screens and functions you would use while *performing*. You cannot, for example, make any reconstructive changes (like adding or changing assignments) but you can certainly return to the HOME screen and operate functions already setup for access.... e.g., you can operate the a Rotary Speaker if it is already assigned, but you could not add it to your Performance while the Sequencer is running.

In the article introducing the new Pattern Features it describes the conditions under which the Warning “Please Stop Sequencer” appears:
Pattern Sequencer Features

In general, while the Sequencer is running you can *perform* (access to all Knob, Quick Edit, Controllers, etc. are available) while access to those settings that attempt deeply to change or re-construct the Performance itself are restricted.

After starting the PATTERN with “Key On Start” either touch “Home” at the top of the first column or press the [PERFORMANCE (HOME)] button. You will find you can navigate where you need, but you cannot make changes that reconstruct the current Performance.

Hi,
I've a similar problem. I've associated, using Live Set, pattern and performance. Si using Live set I could get back the pattern and performance tied together. But every time I power off/on Key On Start is disabled. So I must enable manually. I saved the performance several times. I does not work. Could you please help me?

Many thanks
Domenic