I have changed the main user interface of ModelConverterX a bit, actually it has gone back to some of the concepts that the tool used in 2008 already. I did remove the tabs that were used for the preview, event log and options. Instead of those tabs the options are now on a separate form, which can be opened with the Options button at the top toolbar. The preview and the event log are both shown at the main screen. There is a splitter in between, so you can change the size of the preview and event log as you wish. There is also a button to collapse the event log completely, if you want to maximize the preview. Below is a screenshot of the new user interface.
Why did I change this? Because I think it would be better to have the event log visible while you are working with your object. That way I think it is less likely that users miss an error or warning in the event log.