[Feature Request] Customizing Document Title Per Callback

[justanothercoder99]

Hi, this is a great enhancement! I have a suggestion for further customization regarding the document title updates.

Could we allow specifying the update_title behavior on a per-callback basis?

My reasoning is that not all callbacks require the same title update strategy. The way I would divide callbacks is into two categories -

1. User-triggered callbacks: For these (e.g., button clicks, form submissions), it would be very beneficial to set a dynamic title like update_title="Updating..." to provide immediate user feedback during processing.

2. Automated/Background callbacks: For callbacks like dcc.Interval (which I use for periodic updates or access control checks), changing the document title would be distracting and unnecessary. For these, I'd ideally want to explicitly disable the title update, perhaps by setting update_title=None.

While I have seen suggestions on using clientside callbacks for this, I believe allowing this granular control within dash would significantly improve the user experience by enabling context-appropriate title changes without polluting the title bar for background operations and the developer experience by not expecting the developer to write a clientside callback for every relevant callback. Thanks!

Additional context
Old PR that allows global enable or disable of Document Title update and changing the text of the Document Title when updating #1343
Similar Issue but focuses more on Location and Tabs

[camdecoster]

Thanks for the suggestion! I'll add this to our backlog, but we likely won't be able to get to it any time soon. If you'd like to work on it, we can prioritize a review.

[AnnMarieW]

Hi @justanothercoder99

This would be a nice feature, but I'm concerned that updating the title per callback could be complex and fragile. An alternative might be to add an update_title prop to the dcc.Loading component which would display that title while the component is being updated in a callback.

It would be used like this:

from dash import Dash, dcc, html, Input, Output
import time

app = Dash()

app.layout = html.Div([
 html.H1("My App"),
 
 # Loading component with custom title
 dcc.Loading(
 id="loading-1", 
 update_title="Fetching data...", # new prop!
 children=[
 html.Div(id="data-output")
 ]
 ),
 
 html.Button("Fetch Data", id="fetch-btn"),
])

@app.callback(
 Output("data-output", "children"),
 Input("fetch-btn", "n_clicks")
)
def fetch_data(n):
 time.sleep(2)
 return f"Data loaded {n} times"

[T4rk1n]

I'd vote to remove updating the title updating altogether, it just feel unpolished to me when using an app with tons of callback/interactivity. It's also a performance bottleneck, I added persistent arguments to callbacks for this reason to disable that behavior with websocket callbacks that don't end it was stuck.