I found that the problem is related to that I added a css file called fabric-custom.css to replace some of the styles of my template, which in this case is fabric, if I remove that file, the icon is shown.
On that css file I add some styles like this one
.e-grid .e-headercell {
background: linear-gradient(180deg, #e57a2d 14%, #fca76b 100%);
font-size: 1.5rem;
font-weight: bold;
color: white;
}
So I tried to add the icon there, but it is still not working
I add it like this
.e-property:before {
content: '\e405';
}
This is the order of my css file on index.html on www
<link rel='nofollow' href="css/bootstrap/bootstrap.min.css" rel="stylesheet" />
<link rel='nofollow' href="ImpulsaNet.Client.styles.css" rel="stylesheet" />
<link rel='nofollow' href="css/app.css" rel="stylesheet" />
<link rel='nofollow' href="_content/Syncfusion.Blazor/styles/fabric.css" rel="stylesheet" />
<link rel='nofollow' href="css/fabric-custom.css" rel="stylesheet" />