Can't undo Beautify changes after DIFFzilla?

[rgloden]

Slickedit V22.0.1.0 64-Bit Windows

Steps:
1) Open an Ada File
2) Beautify (default)
3) Right Click the file in tab bar and select "DIFF filename"
4) (Changes shown in DIFFzilla) Close DIFFzilla window
5) Cntrl-Z to undo changes
6) Beautify Changes are not reverted.

[Dan]

DIFFzilla resets undo.  The reason why is that otherwise, you could undo back to the state with the imaginary buffer lines. 

It's a limitation that goes back to the start of DIFFzilla 20+ years ago.  It wasn't such a big limitation then because a lot of products only had one level of undo.  Increasingly (especially over the last year) it's become more noticed and a bigger issue.

I'm working on this and other major improvements to DIFFzilla for the next major release (v2018).

[mjdl]

FWIW for peoples reference, here are two recent threads explaining the situation and some design history & rationale of Diffzilla:
"Undo doesn't work after diff" (80+ comments!)
and
"Undo not working after diff modified file"

[rgloden]

If you are working on DiffZilla, here are a few things in BeyondCompare that would also be nice in DiffZilla:

• BC has a category called "Unimportant Diffs" which are highlighted in a different color, e.g. spacing or comment changes.  The user can define rules (e.g. regEx's) for Unimportant Diffs.  Unimportant diffs can be quickly "ignored" via a toolbar button.
• BC allows you to quickly toggle between viewing just the differences and full text.  It also allows you to define the viewable context surrounding the difference, e.g. the number of lines around the difference.  And when in differences only view, you can expand the context of the difference section(s) for which you need more context.
• BC allows you to select a ranges of lines to merge, e.g. instead of just one Line or Block at a time, you can select multiple lines and then merge to the other side.
• BC allows you to click a line and it then displays that line from both files stacked vertically on top of each other ... helps to quickly understand a nuance difference if you can see each version of a line vertically stacked
• BC allows you from a Windows or Linux file explore, to select two directories and compare them via the right mouse button popup context menu.

[Dan]

FWIW for peoples reference, here are two recent threads explaining the situation and some design history & rationale of Diffzilla:
"Undo doesn't work after diff" (80+ comments!)
and
"Undo not working after diff modified file"

The 80+ comment one was actually moved the feature request forum because there were lots of other good ideas in there too.