Embedded Canvas app Issue with multiple apps

[Poweruser1101]

Hi All,

I have 3 embedded canvas apps on each tab of my CRM form.
Each canvas app has a Save button (created in powerapps) on it to save the data entered on the app.

Issue is when the user navigates to other tab on the CRM Form without saving data , i want to display an error to user that he has not saved data in this tab. firstly how do i understand that there is a change on the form, and if there is a change how should i trigger the error. because clicking on the tab is handled by CRM Form and cannot be dealt in canvas app.

Also Save button on each canvas app will only save the data within that app and will not save data of other apps

I also looked into creating tabs (using buttons) within powerapps and adding all the 3 canvas apps as different screens in a single app. so that when the user clicks "Save" in any of the apps all the data will get submitted but i am not sure in this case will it be able to access the formcontrols of different screens.

Please advice.