find the correct size for a combo in THTMLForm

I want to set the size of a combo in THTMLForm so that combo's options are shown and not get cut.
DropdownSize does not exist, Dpi can make things upredictable.
How can I find the correct size for a combo in THTMLForm?

I'm not sure I understand your question.
Are you referring here to a THTMLComboBox? And what specific is the relation to a THTMLForm?

No, I am talking about a
<CONTROL TYPE="COMBO" ID="'name'" VALUE="'value'" WIDTH="200">
and how to set the optimum width

This is not trivial. There are currently no hooks for this to set it dynamically. The only option for now we see is to dynamically precalculate before you fill the HTML in the cell. We'll reflect on more easy ways to do this.

Thank you for your response