Yes. Drag across the words before releasing and the whole chunk gets translated as one unit. I’ve just tried your example and “dans le cadre de” comes back as “as part of”. It’s saved to your Word List as a single flashcard too, so you can practice the chunk rather than the individual words.
The coral reef behaviour you spotted is the “Merge Phrases” setting, which is on by default. With it on, clicking a word next to one you’ve already highlighted merges the two into a phrase, so you can also build a chunk up word by word instead of dragging. You’ll find it in the reader Settings tab (open a text, click the button at the top right to open the sidebar, then Settings) under Translation Behavior, along with the rest of the options.
@M_C is right about Context Aware translations too. With this enabled you can often get away with clicking single words or shorter phrases and still get the correct meaning because it is taking the surrounding context into account. (This option is only available on the Premium plans though)
Thanks for the kind words, and for sharing Readlang on the TES board. Please let me know if you hit anything else once you’re up and running with your students.