Considering I am the founder of Instagram, it means I have written 100% of the application code by myself, then found an investor and they put some money into the startup and got 30% of the new established company's shares.
Then I decided to make some modifications and change some of the ideas and create another app/company by only myself and name it TikTok! In this new application I may have used some of the codes from my previous app as they have lot of similarities and also the previous app is written by me and I don't know how to write a similar code in a different way! And obviously there are similar ideas between this new TikTok app and my previous Instagram application.
Another example would be the Uber. Maybe the founder of Uber comes up with a new idea "why shouldn't we also transfer food?" And wants to establish a new company and create UberEat application but under a new company and brand name and application name.
Is it possible for the investor of the first app suing me for using some similar codes or ideas to create my new app?