Elvirais wrote:...the open source version supposedly doesn't allow creating closed software, which seems really illogical (since open source creation tools are used so often to create commercial/closed software).
There are almost as many open source licenses as there are proprietary ones. They vary in specific terms, but they all make their source code freely available.
The GNU Public License (GPL) that LiveCode uses for its Community Edition is among the world's most popular open source licenses, used by MySQL, NextCloud, Joomla, Drupal, WordPress, and thousands of other projects.
The GPL expresses no opinion about price; the "free" in "free software" is in the "libre" sense, "freedom", the freedom to have access to the source and to share that source with others. The terms of the GPL also grant those freedoms downstream: a work derived from a software distributed under the GPL must also be distributed under the GPL, so that all users have the same access to source code.
When your goal is sharing code, the GPL is an excellent choice. So when you want to make open source software with LiveCode, the open source edition is available for that.
If you want to make proprietary works with LiveCode, there's a license for that too. While not cheap, it's roughly on par with many other tools that provide high-level GUI support across multiple platforms.
A proprietary license can be a good choice when you want to build a business around selling software on a per-use basis. And at >$3/day, LC's Indy license will be among the smaller costs a startup will have in launching their business, not bad for a code base crafted over many years and well maintained by highly-skilled professionals delivering some 90% of what's needed for multi-platform delivery.
And there's no need to commit to an Indy license just to explore LiveCode. The Community Edition supports nearly every feature in the Indy and Business editions, and the file format is identical among them all. You can start exploring LiveCode with the Community Edition today, and it's only when you need distribute your work to others that you'd need to consider the distribution license. If distributing as open source you'd already have everything you need, and if you want to distribute under a proprietary license you could pick one up at that time.
For further guidance, you may find this FAQ handy - see the question, "Can you give me some examples of where I do and don’t need a commercial license?":
https://livecode.com/resources/support/ask-a-question/