Hello Hafiz,
Edit: To solve the visibility of fields problem, read the answer above, to customize the combobox, read mine.
First of all, create a class in your stylesheet, for this example we will use "custom-combo":
.custom-combo{ border: 2px #00f solid;
}
Assign an OnChange action to this combo box, on that action what you have to do is:
1 - Verify If combo box selected value is now "Custom"
2 - If so, run this javascript code ("RunJavascript" action, from HttpRequestHandler Module):
"
var element = document.getElementById('" + <ComboBox.Id> + "');
element.classList.add("custom-combo");
"
Change <ComboBox.Id> for your combobox name .Id value
To remove the class, in case of the user changes his selection, use this snippet to remove your custom style:
element.classList.remove("custom-combo");
This should solve your problem, if you have any aditional doubts please be my guest ;)
Kind Regards,
JD