The problems in learning bokeh

I am a begginner of learning bokeh, and study the widgets in bokeh. download the python file and run.

$ bokeh serve sliders.py 
2021-03-25 19:55:30,826 Starting Bokeh server version 2.3.0 (running on Tornado 6.1)
2021-03-25 19:55:30,827 User authentication hooks NOT provided (default user enabled)
2021-03-25 19:55:30,828 Bokeh app running at: http://localhost:5006/sliders
2021-03-25 19:55:30,829 Starting Bokeh server with process id: 26985
2021-03-25 19:55:37,213 E-1027 (REPEATED_LAYOUT_CHILD): The same model can't be used multiple times in a layout: Column(id='1043', ...)
2021-03-25 19:55:37,368 WebSocket connection opened
2021-03-25 19:55:37,368 ServerConnection created

here are my screenshot in Firefox after run bokeh serve sliders.py.

bokeh1048×598 32 KB

but the first step guide
shows different, the widgets in my screenshot lacks frequency widget.

@topazus

I suspect the key is the following line from your server log in the terminal window.

This probably means that somehow the amplitude and frequency slider models are considered the same in the layout, and might explain why both (1) the frequency slider is not rendered and (2) the other sliders are not evenly spaced as expected. Note that there is a gap between the offset and phase sliders of your screen capture.

The developers might be better able to help if you provide the actual contents of the sliders.py file as it exists on your computer. (Be certain to use code formatting when adding to this thread.) For example, how did you download it and what branch of the GitHub repo did you get the file from?

When I run the most recent sliders.py file via bokeh server, the output is as expected and without repeated-layout-child errors on bokeh 2.3.0.

Thanks for your time to answer my question. Finallly I find a typo mistake in my code.