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September 11, 2008 /News, Views & Updates /

MDI vs. SDI in Acrobat

On Windows operating systems there are two modes in which applications can display documents: MDI and SDI. In Acrobat 9, we dropped support for MDI. Read more about the reasons for this after the break…

MDI: Multiple Document Interface is when windows reside under a single parent application window.

SDI: Single Document Interface is when all document windows are separate from each other.

MDI is not applicable on the Mac OS. On Mac OS X, an MDI mode does not "save screen real estate" by eliminating redundant menu bars, because the Mac OS X graphical user interface is application-centric instead of window-centric. As opposed to Windows, all windows belonging to an application share the same menu. Therefore, when discussing MDI and SDI it is a Windows specific conversation.

Some of our customers have noticed a change in the viewing modes of Acrobat and Adobe Reader on Windows over the last two versions. Acrobat and Adobe Reader had long displayed documents in MDI mode. In Acrobat and Adobe Reader 7 we introduced the ability to view documents in SDI mode. This was not the default view mode, but a user could enable it in the preferences. In Acrobat and Adobe Reader 8 we made the default mode SDI and still allowed users to choose MDI in the preferences.

Acrobat and Adobe Reader said good-bye to MDI mode in version 9. Probably not noticed by most of you, but some of you have noticed and asked why we did this. The Acrobat Product Management team wanted to share our reasoning with you for this change.

There were several contributing factors that led to this decision.

  1. Feature Parity with Macintosh was desired. As stated before, the Mac OS does not have this option. While I will be the first to admit that feature parity is not 100% between Windows and Macintosh, it is a goal that we aim for.
  2. In version 8, we made SDI the default in the viewing mode. Making SDI default, but still providing MDI in version 8 was done to start the deprecation of MDI.
  3. Microsoft advised that to work as good as possible on Vista, applications should avoid MDI.
  4. Acrobat and Adobe Reader’s new UI modes would not work with MDI. Form editing mode, portfolio mode, and portfolio preview mode all wanted a complete refresh of the UI. MDI mode always left a bit of the UI skin under the care of an MDI main frame, so there would have had been no way for those UI modes to re-skin that part of the UI if MDI mode was left in place.
  5. A cost compelling reason was that MDI and SDI mode essentially became another view mode in which all work flows had to be tested. This increases the cost of testing the product and the cost of fixing bugs. Often a fix to a bug in one view mode would cause adverse reactions in the other view mode. The decision to support only one view mode on Windows was made to simplify this. Furthermore, more time spent in this area could mean less time spent developing and fixing bugs in other areas.

MDI mode seems to have been loved for the aspect of keeping all documents opened by a single application contained tightly together. However, in a world where larger screen resolutions, multiple monitors and the need to see multiple documents at one time has increased, SDI mode offered higher benefits. Couple all this with the requirements coming from Windows Vista and the decision was made to drop MDI mode.

Going forward the Acrobat Product Management team has started exploring alternative ways to accomplish some of what is so loved about MDI mode. While we can’t comment publicly on that at this time, please know that we have heard you. I hope the reasoning I provided helps you understand the choices we made a little bit better as well. Please let us know your thoughts about the removal of MDI support. Let us know what you feel the benefits of MDI are and how it helps you get your work done. We would love to hear from you.

Jeff Moran

Acrobat Product Management


Categories: News, Views & Updates


  • By Pat Ryan - 11:30 AM on September 11, 2008  

    SDI mode in Reader creates too much screen clutter. In my business we are reviewing many individual single sheet drawings at once.

    [Pat – Thank you for the comment. Is clutter the main reason that SDI is not desirable? Are there specific work flows that are made more difficult or impossible because of SDI? – Jeff]

  • By Atin Wadehra - 9:13 PM on September 17, 2008  

    1. As per Glenn Catlin in Acrobat forums “We have 140 Acrobat Pro licenses here, and if you think the loss of MDI is bad on a single monitor system, I can tell you that it’s far worse in a dual-screen environment. For our dual-monitor folks, they can hardly do their job anymore. Acrobat 9 without MDI in a dual-monitor environment does not behave in a way that makes sense.”
    2. As per Matt99, feature was essential for some in-house programs to work correctly, and it’s also a management preference for viewing PDF documents.

  • By Peter Jakacki - 5:41 PM on September 18, 2008  

    I appreciate the technical reasons for going to SDI but like many many others we just don’t view one or two documents at a time. No matter how big the monitor is I’m pretty sure it won’t do a very good job of displaying 10 to 20 documents PLUS all that other software we run besides Acrobat!
    Now I have to switch back to AR8.

  • By Brian Jongekryg - 8:34 PM on September 18, 2008  

    I’ve gone back to Acrobat 8 because of the loss of MDI mode. I use Acrobat for creating PDFs but more often, I use it to view PDFs and usually have 5-10 documents open at a time (and sometimes more). Along with probably 20-30 windows from other applications all running. What MDI gives me is – a) less screen clutter, b) minimize all PDFs by minimizing just one window, c) easily move Acrobat from one virtual desktop to another as needed since it’s just one window.

  • By L Marable - 7:23 AM on September 19, 2008  

    Unfortunately I have to stay with AR9 as our corporate HQ designs documents in that format. However, opening 15-20 documents and having them comepletely fill my screen is not the way I would prefer to work.

  • By C. Turner - 1:36 PM on September 19, 2008  

    I will be returning to version 8 as well. We are required to have many PDFs open at once and I’m finding the SDI mode a huge pain. In my job, I’m reviewing artwork for packaging and there is nothing new in version 9 that warrants it staying on my computer. Sometimes newer isn’t better.

  • By Skip Straus - 1:58 PM on September 19, 2008  

    I was pretty irritated when I looked for the MDI/SDI selection command and couldn’t find it. I’m calmer now that I’ve spent the 20 minutes to find this place and register for the forums and …
    Your explanation is thoughtful and thorough, and of course testing multiple features and the costs is important.
    Nevertheless, Microsoft Office pretty much validates the value of the MDI/SDI option. Same with tabs in modern browsers. In my work with most programs on Windows XP and Vista, MDI is the preferred mode because I can do more work faster. So this decision is costing me money now. And time.
    MDI saves screen real estate by not having to duplicate one’s menu and toolbar settings.
    Please bring back MDI and if possible, include the ability to tile the documents in the Window menu.
    Now I need to evaluate the return to Reader 8.

  • By Burkhard Kaas - 7:27 AM on September 20, 2008  

    I fully agree with previous comments. SDI might be nice for a few documents, but we usually have a lot of documents (technical datasheets, sometimes 20-30 ore more) open. Especially using dual monitors, it’s almost unusable. Usually we use a secondary monitor for PDF viewing and the main monitor for engineering.
    What is hurting most:Opening a new document opens a new window with different size and position as the other Acrobat windows. Most of the time on the wrong monitor. That means, you have to change the window from maximized to window mode, move it to the correct monitor, and back to maximized. If you just want to flip through a numer of documents, this increases time by a multiple.
    If I have a lot of documents open on the main screen, flipping through technical documentation, and want to do CAD, I have to move all the documents manually to the secondary screen.
    When I work on a single screen display, we have a few applications open, like CAD+Acrobat+Excel+Explorer. With MDI I can easily flip between CAD and Acrobat using Alt-Tab, returning me to the previous view in both applications. With SDI, I have to flip through all documents open. Fortunately Office still supports MDI. Consider the scenario: 20 datasheets open in Acrobat, 15 excel sheets, 10 CAD drawings. This is not hypothetic, this is real live. If all these apps use SDI, this gives 45 windows. You get lost in your windows!!!
    Basically, what could make SDI acceptable for me, would be a feature, that forces all windows to be same size and position. Moving or resizing one window would move and resize all the other windows.
    We have stopped buying Acrobat 9. If Acrobat 9 stays like it is, we will downgrade all Acrobat 9 installations to Acrobat 8. We loose too much efficiency.
    BTW: Acrobat 9 likes to crash frequently when many documents are open. We are using the Pro version. Looks like Acrobat has problems with more than a few documents open at the same time. This was not a problem with previous versions.

  • By Alex W - 5:55 PM on September 20, 2008  

    I have to agree; SDI mode is very cluttering to my workspace. I often open multiple documents when performing search, comparisons, and lookups. SDI mode is not well suited for what I do. Additionally, the “taskbar real-estate” (e.g. number of buttons) becomes absurd when working with multiple documents that prefer to open distinct windows. Switching with CoolSwitch (Alt+Tab) becomes more troublesome, as I would like to switch between programs and not documents with such a global hotkey. (Consider, for example, switching between Word and Reader, the last two used programs versus switching between Reader and Reader, with the last two documents viewed.)
    Please consider bringing MDI back as an option. I’m fine with SDI as a default, but SDI-only makes life much more difficult.
    If I haven’t made it clear enough, SDI is A Bad Thing for several of us. MDI is preferred, and it would be fine even as a plugin, add-in, or non-default option.

  • By Jeff Moran - 9:35 AM on September 22, 2008  

    Thank you for your feedback. I’m working on a follow up article to provide some more thoughts and possibly work-arounds. In the mean time, be aware that we’ve posted a Support article on the issue
    here with one work-around. We’ll be updating this article as well as we are able to share more.
    Thanks again for your comments.

  • By Rob Nussbaum - 4:51 PM on September 22, 2008  

    I have to join the chorus of those who desparately miss MDI. Much of what I do depends on side-by-side comparisons and alt-tabbing back to the DTP programs I’m running concurrently (InDesign, FrameMaker, Quark). Losing the ability to toggle on a program level has definitely decreased my efficiency.
    It’s disappointing that each “upgrade” to Acrobat seems to take away functionality, such as using mouse buttons for previous view.
    On an unrelated note, the Compare Documents feature in Acrobat 9 Pro so far seems very buggy (it has crashed several times) and less intuitive than in version 8 (the Document Description options are limiting). Not ready to “downgrade” yet, but it’s a consideration.

  • By Ray Mansell - 7:12 AM on September 25, 2008  

    Add me to the list of frustrated users who will be reverting to an earlier version of the reader. Like them, I typically have several documents open at one time, and the resulting clutter is simply unacceptable.
    The posted work-around (grouping similar taskbar items), while workable, is anathema to me since I detest that feature of Windows, so I’m hoping you will find a way to bring back MDI in future releases. Hmmm… I suppose if one could selectively group taskbar items (say, just the Acrobat Reader ones), I think that might work – but I suspect you have no control over that.
    In any case, thank you for listening and responding to our concerns.

  • By sjk20 - 12:10 PM on October 1, 2008  

    I hate SDI mode. Browsers with tabs have now been around for a long time. This is a giant step backwards.
    Ease of use for developers is a lame excuse.
    I will be going back to AR8.

  • By Muhammad Sorcar - 3:45 PM on October 1, 2008  

    Taking MDI off Windows version to bring compatibility with Mac hardly seems to be a persuasive argument for the vast majority of Windows workers. Everybody uses Acrobat (Reader)!
    I have to open about 50 incoming faxes every morning in acrobat. Now it completely clutters my screen and buries other programs running. I can very well keep multiple tabs in a single Firefox window, but have no way of doing such in AR9.
    I have decided to stick to AR8 and only hope that MDI will be reintroduced, like Microsoft, which removed it from Word once, but reintroduced as an option due to popular demand.

  • By David Stromfeld - 9:37 AM on October 7, 2008  

    Thank you all for the feedback on this issue. We’re heard you loud and clear, and we’re working to figure out what is the best way we can make this issue better. Therefore, I’m going to close any more comments on this topic. You all are corroborating each other’s sentiments, so there’s no need to beat a dead horse.
    The Dead Horse
    (Dave Stromfeld, Product Manager)