When the "Change Slide Master" dialog is opened, I suggest the default choice be the last master which was chosen as a replacement for the currently-applied master - if such a master exists; otherwise let the default choice be the current master (as is the case right now). Rationale: If someone opens this dialog, they typically do want to change the master, and the most likely choice (AFAICT) is their last choice for a change. If we don't have information about what they are likely to want - then defaulting to "do nothing" is reasonable.
Sounds like over-engineering. And the assumption you do repetitive operations is also questionable - you can select multiple slides and apply an operation to all. Meaning the use case is for different presentations. => NAB
Default opening to the currently applied slide design (aka. master) seems more functional--less chance of applying an undesired design. Also use case of opening the dialog allows one to identify/preview features of the master as currently applied, or the description and preview of the other master slides in the template--not necessarily an intent to actually change the applied slide design. Suitable to task as is... -1
(In reply to V Stuart Foote from comment #2) > Default opening to the currently applied slide design (aka. master) seems > more functional--less chance of applying an undesired design. Well, if you open the "Change Master Slide" to change the master, then the current master is undesired, isn't it? > Also use case of opening the dialog allows one to identify/preview features > of the master as currently applied, or the description and preview of the > other master slides in the template--not necessarily an intent to actually > change the applied slide design. That's a valid argument. Closing.