Clicking the collection “eye icon” in Blender 2.8 outliner shows and hides the visibility of objects from this collection in viewport window. To show only objects from the necessary collection and hide objects from all other collections with a single click – click the “eye icon” with the “Ctrl” button pressed.
In Blender 2.8 the toolbars are located on the top of the working windows. But you can easily return them to the habitual bottom position.
Right-click on the panel and select “Flip to Bottom” to move the panel down. To return the panel back to the top, right-click on it and select “Flip to Top”.
This feature is not Blender 2.8 exclusive, the same can be done in Blender 2.7.
In the new Blender 2.80 in the “3D View” window (3D Viewport), when scrolling a wheel to zoom or pressing the num pad buttons (1, 3, 7, 9) to center the view to different sides, the projection mode automatically changes between orthographic and perspective.
To disable this automatic mode changing, in the “User Preferences” window – “Interface settings”, change the value of the Auto Perspective checkbox:
State switches so-called “radio buttons” are used in the case to limit the choice by one value from several available ones. There are a lot of such buttons in the Blender interface, for example, switching between RGB and BW rendering modes or setting the texture mapping mode. Such buttons can be created in the Blender add-ons interface too.
Let’s create our own radio button switcher.