python streamlit sidebar resetting on entry of input

I am creating a streamlit app where on the sidebar I have first a file uploader and a button. Once the file is uploaded and then the button is pressed, it shows more input option and two more buttons for user to finally sumbit. When I am at the second step, after user enters the input, it resets the sidebard to go back to step 1 and earlier hidden options go back to hidden.

Here is my code:

    file = st.sidebar.file_uploader('Upload',type=["pdf","txt"])
    #this is step1
    if file is not None:

        # Save uploaded file to 'F:/tmp' folder.
        save_folder = 'F:/tmp'
        save_path = Path(save_folder, file.name)
        with open(save_path, mode='wb') as w:
            w.write(uploaded_file.getvalue())

        with st.sidebar:
            if save_path.exists():
                st.write("File uploaded")

    co1, co2= st.sidebar.columns([1, 1])
    
    submit = co1.button("Submit", use_container_width=True)

    if submit:
        input1, input2, input3 = compo() # local function which sets streamlit sidebar inputs
        st.sidebar.markdown("---")
        c1,c2 = st.sidebar.columns([1,1])
        reset = c1.button("Reset", use_container_width=True)
        fin_submit = c2.button("Final Submit", use_container_width=True)
        
        #When I enter input1 and then go click to enter input2, it resets to step 1

        if reset:
            placeholder = st.empty()
            

        if fin_submit:

            if file is not None:
                
                if (input1 == "Hello") or (input2 == "There"):
                    placeholder.empty()
                    # Call processng function and display result
                else:
                    placeholder.empty()
                    st.error("Sorry!")

            else:
                if (input1 == "You") or (input2 == "there"):

                    
                    placeholder.empty()
                    # Call processng function and display result
                else:
                    placeholder.empty()
                    st.error("Sorry!")

Here is the code for compo():

def compo():

    
    c1,c2 = st.sidebar.columns(2)
    input1 = c1.selectbox(label = "Input 1",options = ['Hello',"You"])
    input2 = c2.selectbox(label = "Input 2", options = ["There","there"])
    input3 = st.sidebar.slider("Number",min_value=1, max_value=10, value=1, step=1)
    st.sidebar. markdown("---")
    return input1, input2, input3

I don't know why as I enter a value in input1, it resets to step1

Buttons do not retain state. They return True on the page load resulting from their click and then immediately go back to False. If you nest something inside a button, it will go away as soon as the user does something (because the page reloads and the button becomes false).

See the first point in this blog post.

Here's another answer for a similar question.

To nest buttons, you can track a boolean flag that gets set to True by a callback function:

import streamlit as st

if 'submitted' not in st.session_state:
    st.session_state.submitted = False

def submit():
    st.session_state.submitted = True

st.button('Submit', on_click=submit)

if st.session_state.submitted:
    st.write('The submit button was clicked.')
    st.button('Do nothing')

Since the 'Do Nothing' button is conditioned on the 'submitted' value in session state instead of directly on the output of the 'Submit' button, it will stay on the screen when clicked.