What was the drama between Wordpress and Thesis about? This is my first time hearing about it.
The spat ran for a few years back around 2010.
Thesis (Chris Pearson, DIYThemes) locked down their theme and didn't allow others to access the code, add-on features and pass on the rights to use them as required by the GPL (GNU Public License).
WordPress (Matt Mullenweg) accused Thesis of violating the terms of the GPL. Thesis said that it was their work and their theme so they had the right to lock it down and make it proprietary. WordPress fired back that it was built on the WP platform and had to comply with the GPL. WP threatened to sue Thesis to enforce the terms of the GPL. Not sure he would have gone that far because it's expensive and time consuming. But he was really pissed off, it seems.
In the end Thesis backed down - sort of. They offer a split license.
They added the GPL license to their TOS and it covers all of the WordPress based code in PHP. But they also issue a Proprietary Use License that covers the non-PHP pieces of code such as CSS, Javascript files and images. These elements are copyright to DIYThemes and not open for sharing and modification.
This split license arrangement seemed to end the battle.
At the time Thesis Theme was a very powerful and popular theme so the battle got a lot of attention. Thesis has since lost a lot of its popularity and they way it implements WP is clumsy and difficult to work with. Other Themes and frameworks have surpassed Thesis in design and usability.
I found a couple of articles searching Google but I remember when it was blowing up big-time.
Lawsuit Averted As WordPress and Thesis Settle Differences Over Themes And The GPL
https://www.techdirt.com/articles/20100719/01305210269.shtml
WordPress vs. Thesis: The battle is over
https://crunchify.com/wordpress-vs-thesis-the-battle-is-over/
I have a lifetime paid license for Thesis DIYTemes from back in the day. I still have my access but I haven't used Thesis in a long time. They did a big redesign a few years ago and earlier versions no longer work. It is a real pain to use and updating to a new version trashed my websites. Also, switching to another (non-Thesis) theme causes huge problems because of the way Thesis integrates content with their theme.
Most big publishers now, like ThemeForest, follow the GPL. They leave their theme code open and allow sharing/reselling of their themes. They make money by offering a paid membership model so "authorized' users have access to theme updates and technical support. This is the monetization model preferred by WP.
EDIT: As mentioned by
@Dark Sky, there are "grey areas". WP claims that everything in the theme sources files (including CSS, images, etc.) should be under GPL. Others argue that non-PHP, non-WP code (like Javascipt and CSS) and images are not part of the WP code base and therefore cannot be forced to comply with the GPL. WP dropped the argument with Thesis when DIYThemes adopted a split-license model so these "grey areas" have never been tested in a court.