Docs:  Updated note to enable VPR's GUI
@@ -23,6 +23,8 @@ In general, please follow the steps to compile
.. note:: recommand to use ``make -j`` to accelerate the compilation
+.. note:: VPR's GUI requires gtk-3, and can be enabled with ``cmake .. -DVPR_USE_EZGL=on``
+
**Quick Compilation Verification**
To quickly verify the tool is well compiled, user can run the following command from OpenFPGA root repository
