Yes, views on your dashboard will often times automatically re-size to fit its container. If you take something out, views may become larger. If you drag and drop a new view somewhere in the dashboard, other views may shrink to allow enough space. Even if you adjust the height of a dashboard and the existing view(s) fill up the new space, you can still drag in your other worksheets.
With a floating object, you can set the X, Y, height, and width. Most of the time it will remain placed properly when the width of the dashboard changes.
With a non-floating object, you cannot specifically lock in a placement. The placement is dependent on how you organize the views and containers in the dashboards, and where you place new views.
Locking section sizes:
If you put a view inside a Vertical or Horizontal container, you can set a fixed height (in Vertical containers) or a fixed with (in Horizontal containers).
When your view is in one of these containers, click the view, then on the down caret in the top-right menu. You'll find the option to "Edit Height" or "Edit Width", depending on the container.
If you need any further explanation on layouts, feel free to ask.
Here are a few topics to tell you more on layouts:
Note: The Fit Selector (where you select Normal, Fit Width, Fit Height, and Entire View) may also impact automatic sizing. Be mindful of that.