Why does the dashboard layout, within a given tab, completely rearrange when adding an additional element to said tab? This is quite frustrating actually. I spent considerable time getting items placed as desired, and then added an additional item in a flow, a ui text item. The result was everything was completely moved around in the associated dashboard the tab, some type of automatic formatting. It completely ruined the work previous.
When you add a new item, try to ensure it gets added to the bottom of the list in the dashboard sidebar. If you copy/paste an existing widget it'll probably get added next to the original instead.
Also the layout engine seems to work best if widgets are the same width or exact multiples thereof.