As well as being able to toggle the width of a Bloc you can also toggle a full height setting.
What do we mean by full height? Basically we mean the Bloc will always be at least as tall as the screen it's being viewed on. If the screen is very small and/or there is enough content within the Bloc then it might be taller.
To change the height find the Bloc you want to change and click to show the editing bar. Then click the two up and down arrows to toggle between its initial height and a 100% height.
To illustrate the difference the following two images show a Bloc at it's initial height, followed by being toggled to 100% (for demonstration purposes a full HD 1080 screen was used).