This was one of my qualms with Code::Blocks when I started using it. I’m used to working with VSCode and even with Visual Studio which have the feature that allows you to return to the previously active tab with Ctrl + Tab. While it might be a little annoying to get used to at first, it’s a really handy feature.
In Code::Blocks the same key binding does something else, it switches to the next tab in the chronological order that they are placed on the dashboard. For this reason, I began to search if there was any possibility of there being a way around this. What I found was surprisingly simple. The shortcut here is Alt + Arrow_Key. Might take a little getting used to, but I am glad that it exists!