Try a little script.
// https://resource.dopus.com/t/paste-files-to-telegram/47405
function OnClick(clickData) {
DOpus.SetClip(clickData.func.sourcetab.selected);
}
Button as XML
<?xml version="1.0"?>
<button backcol="none" display="both" label_pos="right" textcol="none">
<label>CopyFilesFromCollection</label>
<icon1>#clipcopy</icon1>
<function type="script">
<instruction>@script JScript</instruction>
<instruction>// https://resource.dopus.com/t/paste-files-to-telegram/47405</instruction>
<instruction />
<instruction>function OnClick(clickData) {</instruction>
<instruction> DOpus.SetClip(clickData.func.sourcetab.selected);</instruction>
<instruction>}</instruction>
</function>
</button>