Feature: Drag-and-drop text should only be one change, allowing a single `undo` to undo it

[JFormDesigner]

Only a minor issue, but when I undo drag-and-dropped text then I have to press Ctrl+Z twice.

In other editors a single Ctrl+Z undoes a drag-and-drop.

[JordanMartinez]

How quickly after dropping do you press CTRL+Z? Is this still the case after waiting 500 ms?

[JFormDesigner]

Yes, this is still the case when waiting longer than 500ms.

[JordanMartinez]

I'm guessing the first undo deletes what was dropped and the second inserts what was dragged, correct?

I'd guess it has something to do with #526.

[JFormDesigner]

I'm guessing the first undo deletes what was dropped and the second inserts what was dragged, correct?

Yes, exactly.

I'd guess it has something to do with #526.

Don't know, but in 0.7-M3 I have to press Ctrl+Z also twice. So probably older issue...

[JordanMartinez]

To be honest, I can't fathom how else it would work. EditableStyledDocument#replace does not allow one to remove text in one spot and reposition it elsewhere in a single change. That requires two changes: delete the text and then insert the text.

[JordanMartinez]

I think this should be a feature request.

[JFormDesigner]

Sure, there are two text changes.

OK, I think I understand the problem: the undo system does not support compound changes (multiple independent text changes).

I remember that I already had this problem in the past in Markdown Writer FX. E.g. if the user presses Ctrl+B to mark the selected word as bold, I first inserted ** before and after the selection, which resulted in two undos. I worked around this problem by doing a single text replace with **selection**.

Found several methods where I'm doing single text replace to keep undo history clean:

• https://github.com/JFormDesigner/markdown-writer-fx/blob/dc9e6a7ba37de9879116748df04fc6cf514ee4fe/src/main/java/org/markdownwriterfx/editor/SmartEdit.java#L531-L533
• https://github.com/JFormDesigner/markdown-writer-fx/blob/dc9e6a7ba37de9879116748df04fc6cf514ee4fe/src/main/java/org/markdownwriterfx/editor/SmartEdit.java#L458-L459
• https://github.com/JFormDesigner/markdown-writer-fx/blob/dc9e6a7ba37de9879116748df04fc6cf514ee4fe/src/main/java/org/markdownwriterfx/editor/SmartEdit.java#L483-L484
• https://github.com/JFormDesigner/markdown-writer-fx/blob/dc9e6a7ba37de9879116748df04fc6cf514ee4fe/src/main/java/org/markdownwriterfx/editor/SmartEdit.java#L770-L773

I really like to see some API to support compound undo. E.g.

undoManager.compoundChange(() -> {
    // do multiple inserts or deletes here
});

Think this is a must have feature for complex text operations in . E.g. mark bold, move lines, fix all spelling errors, rename occurrences, etc

[JordanMartinez]

Actually, changing the change type from RichTextChange to List<RichTextChange> is one of the steps needed for implementing #222. To keep source compatibility, we could change GenericStyledArea's API to:

public void replace(int start, int end, StyledDocument document) {
    replaceMulti(Collections.singletonList(Tuples.t(start, end, document));
}
public void replaceMulti(List<Tuple3<Integer, Integer, StyledDocument>> changes) {
   content.replaceMulti(changes);
}

where (EditableStyledDocument) content.replaceMulti will call replace multiple times, storing the changes made, and then emitting the result.

[Adrodoc]

I just ran into the same issue while implementing Tab/Shift+Tab indent/outdent, I think this is a highly desirable feature. For now i guess I'll replace the entire text section and manuall set the cursor and anchor positions after the change.