When editing a long node name in Free Mind on desktop you can enter a line break by using "shift-enter", then a simple "enter" would confirm the edit.
This same Free Mind mind map when transferred to Android and edited with Thinking Space would display the node with line break correctly. However, I couldn't find a way to enter that line break in Thinking Space. I tried the following input methods: Swype, TouchPal, Hacker's Keyboard.