I do not see where there is a problem. What you want to do is possible, but not with a single command like Alt+Tab does for applications. The multi-document interface of Microsoft offers for this task the commands Next (Document) Window with standard hotkey Ctrl+F6 and Previous (Document) Window Ctrl+Shift+F6. All Windows applications using Microsoft's MDI support this method.
A detailed step by step description how these 2 commands of MDI works. Let's assume you have 10 files open.
- The active file is file 2. You want to switch to file 8.
- You need to do this the first time with mouse clicking on file tab of file 8.
Or you open menu Windows (by key) and press the key of the document window listed at bottom you want to jump to. Usually there are only the last 4 document windows listed, either in order of the file tabs (special feature of UltraEdit) or in recent used order (MDI default enabled by checking configuration setting Old-style window list at Advanced - Configuration - Application Layout - Advanced).
There is also the command Windows in menu Window listing all document windows for activating or closing. That's also a standard feature of Microsoft's MDI and in UltraEdit a hotkey or chord can be assigned to the WindowListWindows command too.
And another document window can be activated also directly via Open list in File Tree View.
- Switching back to file 2 can be done with Ctrl+F6.
That's confusing, I know that. Command Next Window moves back to previous document. It is easier to understand this behavior by enabling Old-style window list and looking on list at bottom of menu Window to better understand this behavior as designed by Microsoft. The document window of the file active before current active file is at top of the list of document windows. The command Next Window activates the document windows in this list from top to bottom. The command Previous Window activates the document windows in reverse order from bottom to top. In my point of view it would be more intuitive that Ctrl+F6 is assigned to command Previous Window and Ctrl+Shift+F6 to command Next Window. That can be done in UltraEdit. But be aware that doing this in UE could confuse you if you use these two hotkeys in other applications like Microsoft Word, Excel, Adobe Reader or browser too.
- Now you want to switch again to file 8. This time Ctrl+Shift+F6 must be used and not Ctrl+F6.
- To switch back to file 2 it is needed to use again Ctrl+F6.
- To switch back to file 8 it is needed to use again Ctrl+Shift+F6.
In other words you can switch between the 2 last activated document files by using alternately Ctrl+F6 and Ctrl+Shift+F6.
Why has Microsoft in MDI managed the document window list not like the application list so always the same command can be used to switch between 2 document windows? Sorry, I don't know.