Font size of stickies keeps changing although set to a certain value on all skins in options

Hi all,

I hope to get some answers here. I have the following issue that whenever I type in a sticky, the font size is not what I would expect and how I set it in the options on the skins.
When I use the "set to style" option it does change to the correct size, but whenever I start typing again in that same sticky it is another font size again (much smaller). I had this in version 8 and also now in the latest version 9.0e

My font size on all my skins is set to "Microsoft Sans Serif" Size 9.

Kind regards,

Koen