I was facing a bizarre behavior with the Blazor Bootstrap Tooltip. If I tried it using Console.WriteLine(string? value);, the newline is applied properly, but when I specify them in the Tooltip's Title, they aren't.
In my Razor page, I initialize the Title value by this way:
<Tooltip Class="ps-1" Title="@imageNotes.ToString()" Placement="TooltipPlacement.Right"><Icon Name="IconName.InfoCircle" Color="IconColor.Info" /></Tooltip>@code { private FormattableString imageNotes = $"1. Maximum 8 images can be uploaded\n2. Image size between 330x330 and 5000x5000 px. Max file size: 3MB\n3. Obsceme image is strictly prohibited."; protected override void OnInitialized() { Console.WriteLine(imageNotes.ToString()); }}I'll provide a screenshot for you to see how it actually behaves.
Console.WriteLine(string? value) output:

The same with the output using dotnetfiddle.
Tooltip output:

Other attempts are as follows:
By using string
<Tooltip Class="ps-1" Title="@imageNotes" Placement="TooltipPlacement.Right"><Icon Name="IconName.InfoCircle" Color="IconColor.Info" /></Tooltip>@code { private string imageNotes = "1. Maximum 8 images can be uploaded\n2. Image size between 330x330 and 5000x5000 px. Max file size: 3MB\n3. Obsceme image is strictly prohibited."; protected override void OnInitialized() { Console.WriteLine(imageNotes); }}By using this solution
<Tooltip Class="ps-1" Title="@($"{imageNotes.Replace("@", System.Environment.NewLine)}")" Placement="TooltipPlacement.Right"><Icon Name="IconName.InfoCircle" Color="IconColor.Info" /></Tooltip>@code { private string imageNotes = "1. Maximum 8 images can be uploaded@2. Image size between 330x330 and 5000x5000 px. Max file size: 3MB@3. Obsceme image is strictly prohibited."; protected override void OnInitialized() { Console.WriteLine(imageNotes.Replace("@", System.Environment.NewLine)); }}By using \n directly in Tooltips's Title
<Tooltip Class="ps-1" Title="@($"1. Maximum 8 images can be uploaded\n2. Image size between 330x330 and 5000x5000 px. Max file size: 3MB\n3. Obsceme image is strictly prohibited.")" Placement="TooltipPlacement.Right"><Icon Name="IconName.InfoCircle" Color="IconColor.Info" /></Tooltip>By using this solution directly in Tooltips's Title
<Tooltip Class="ps-1" Title="@($"1. Maximum 8 images can be uploaded{System.Environment.NewLine}2. Image size between 330x330 and 5000x5000 px. Max file size: 3MB{System.Environment.NewLine}3. Obsceme image is strictly prohibited.")" Placement="TooltipPlacement.Right"><Icon Name="IconName.InfoCircle" Color="IconColor.Info" /></Tooltip>They all produce the same outputs. My simple question is: Why can't I format the string with a newline using \n or System.Environment.NewLine in the Tooltip's Title?