QLineEdit has some limitations; in particular, it is difficult to modify the undo behaviour. The new widget LineEdit derives from QPlainTextEdit and has better undo behaviour and also it will be easier to modify the undo stack for it in future should that be necessary. QLineEdit does not allow you to do that and the only ways to modify the undo actions is very hacky (like event filtering the undo key combination, but then it does not apply to undo via context menu, among other issues)
QLineEdit has some limitations; in particular, it is difficult to modify the undo behaviour. The new widget LineEdit derives from QPlainTextEdit and has better undo behaviour and also it will be easier to modify the undo stack for it in future should that be necessary. QLineEdit does not allow you to do that and the only ways to modify the undo actions is very hacky (like event filtering the undo key combination, but then it does not apply to undo via context menu, among other issues)
Fixes #5