Repro Steps:

1) Create a Page
2) Drag an Element to the Page's RootGrid
3) Select the Element using the Selection Tool [V]
4) Switch to the Transform Tool [Y], and whilst holding [Shift], click-and-drag one of the corners of the Element by its adorners.

Observe how the original aspect ratio of the element before it was clicked-and-dragged is not retained.

Expected Results: Holding the [Shift] Key should enforce a Proportional Resizing for any Stage/Viewport element.
(Line 67 of the Studio Shortcuts Sheet: https://docs.google.com/spreadsheets/d/1jbT2X8damp_saIY5tAGgqAPyVo6YIff5xPXkCVaplN4/edit?gid=0#gid=0 )