Here's a discussion about disappearing scrollbars on c2 about "Long Enough To Force An Elevator Into The Scrollbar Discussion" that mentions Smalltalk-80's and Squeak's scrollbars, that float just OUTSIDE of the window, and DISAPPEAR when not required, so they don't taking up extra horizontal space in the window, or re-flow the text when they appear and disappear. Interlisp-D also had this kind of disappearing scrollbar.

http://wiki.c2.com/?LongEnoughToForceAnElevatorIntoTheScroll...

>Squeak floats the scrollbar just outside the window when necessary, and only when the mouse floats over the pane. Bizarre. Apparently you can change this, but the magic scrollbar is as described.

>Bizarre by today's standards, yes. But also traditional and historical. Squeak's scrollbars, not surprisingly, are just like Smalltalk-80's scrollbars, which pre-dated all of the modern scrollbars. Commercial Smalltalks like VisualWorks allow you to change this and other look and feel items (didn't see a way to do it in Squeak right off). IMHO Smalltalk's scrollbars are easy to use and more powerful once you get used to them. For example you don't have to move your cursor up to an arrow button to scroll a line at a time. -- RandyStafford

Here's a demo of Smalltalk disappearing scrollbars from Brad Myers' "All The Widgets" (Xerox PARC & ParcPlace Systems Smalltalk, 1977):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=3m56s

>In this version of Smalltalk, the scrollbars pop up when the mouse pointer enters the window. The scrollbar has three regions. The one on the right: clicking there causes the text to move up. The one on the left: causes it to move down. And the one in the center can be used to scroll smoothly to arbitrary portions of the total text. The square rectangle with respect to the entire scrollbar indicates the fraction of the text that you see.

Here are some illustrations and a description of the disappearing scrollbars from Smalltalk-80, The Interactive Programming Environment, by Adele Goldberg, Xerox PARC:

http://sdmeta.gforge.inria.fr/FreeBooks/TheInteractiveProgra...

p. 33> Figure 2.1

p. 35> Figure 2.2c

p. 37> A scroll bar is a rectangular area, displayed adjacent to the left side of the view it controls. The scroll bar appears in the active view only when the cursor is actually inside the view. If you move the cursor outside the view (without pressing a button), the scroll bar will disappear. It will appear as soon as you move the cursor back inside the viewing area. Thus the scroll bar is a useful visual cue that the view will notice your typing or button pressing. Scroll bars appear only in those views for which scrolling is appropriate, typically in any view in which text can be edited or in list menus.

p. 38> Figure 2.3

The first hidden scrollbars were actually implemented in Bravo at Xerox PARC in 1974. They were just an blank region at the left edge of the window, that changed the cursor to an arrow icons when you entered the region and pressed any of the three buttons.

Here is a demo of Bravo scrollbars from Brad Myers' "All The Widgets" (Xerox PARC Bravo, 1974):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=3m06s

>When the cursor enters Bravo's scrollbar, it changes shape to indicate that scrolling is enabled. Each of the three mouse buttons corresponds to a scrolling operation. When the mouse is depressed, the cursor shape indicates the enabled scrolling action. When the mouse button is released, the command is invoked. Scroll up moves the line of text adjacent to the cursor to the top of the document window. Scroll down moves the line of text at the top of the document window to be adjacent to the cursor. Thumb causes the entire document to jump to the location in the document corresponding to the vertical position of the scrollbar. The boxed arrow indicates the location in the document that is currently visible.

Here's a demo of Interlisp-D disappearing scrollbars from Brad Myers' "All The Widgets" (Xerox Corporation Interlisp-D, 1980):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=4m25s

>Scrollbars in Interlisp-D appear on a window only when they are needed. The user indicates this by rolling out of the content area of the window, into the left or bottom margin. What appears is a scrollbar showing the position of the material that is visible as a small section which is grayed out. The length of this indicates how much is actually visible. Scrolling can be done by using the left button for going up, and the right button for going down. You scroll farther the farther you are away from the top of the window. In addition, the middle button is used to thumb to the place in the whole document that you want to see.

Xerox Development Environment and Xerox Star abandoned the idea of disappearing scrollbars, and Xerox Star moved them to the right edge of the window.

Here's a demo of Xerox Development Environment scrollbars from Brad Myers' "All The Widgets" (Xerox Corporation XDE, 1981):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=5m52s

Here's a demo of Xerox Star scrollbars from Brad Myers' "All The Widgets" (Xerox Corporation XDE, 1981):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=6m36s

Apollo Computer's Display Manager didn't have scrollbars at all, and just let you scroll with the keyboard.

Here's a demo of Xerox Star scrollbars from Brad Myers' "All The Widgets" (Apollo/HP Display Manager, 1981):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=7m19s

Xerox PARC's Cedar document editor Tioga had invisible scrollbars on the left edge, that became visible when you pointed at them.

Here's a demo of Xerox Star scrollbars from Brad Myers' "All The Widgets" (Xerox PARC Cedar, 1982):

https://www.youtube.com/watch?v=9qtd8Hc90Hw&t=8m21s