With ARCHICAD 21 Update 5021 release, having Favorites Palette open in a project will result in performance degradation affecting the responsiveness of ARCHICAD. Lag varies on the operation command executed and some operations seem to be heavily affected by this issue. For instance, placing a wall or moving an object with the Favorite Palette open will cause a slight lag in the operation, while entering custom text in a dimension will trigger a considerate delay during text input.
If this performance drop is frequently affecting your work speed, close the Favorite Palette when is not needed. A permanent fix is scheduled for an upcoming update.