Hi! There must be a mistake somewhere. See the docs of eventLayout.
It says
stack, adjusts row height (only horizontal)
mixed, allows two events to overlap, more packs (only vertical)
Now open your vertical demo
https://bryntum.com/products/schedulerpro/examples-scheduler/vertical/
Check the layout in console
scheduler.mode
'vertical'
scheduler.eventLayout
'stack'
Then when you use Layout Button to change the layout you cannot return to stack which is according to the docs sounds logical. The doc doesn't say what default value is. Shouldn't it be the "pack" by default? Maybe for both Vertical and Horizontal to make them unified.
Please update docs and the default value of eventLayout
for vertical mode if you think it is a reasonable request.
Cheers!