You have activated "Touch Mode". Touch mode makes the user interface easier to interact with when you use a touch-enabled device. It optimizes the size of on-screen manipulators, context toolbars, breadcrumbs, and selection.
You can turn it on/off from the "View-Touch Mode" menu item.
For more info on Touch Mode check out 2018 SOLIDWORKS Help - Touch Mode
I hope this helps,
Thanks John, that was it. Just got 2018 and had never seen this feature before.