Manually saving chat transcript - Plain text as default?

Hi,

I’ve set my preferences of my Embedded Sametime client in Notes 8.5.1 to prompt me to save chat transcript. It prompts me to save chat with the options to save either as Rich Text or Plain Text. I always prefer to save as Plain Text. But the Rich Text is selected by default and I’ve to do an extra click to select Plain Text always. Is there any option to set Plain Text as the default for manually saving chat transcripts?

Thanks.