Save as clears history
Save as clears the document undo history, i'd rather it wouldn't. Say you accidentally saved a document in stead of saving as — next you 'save as' so your new work isn't lost — next you wanna undo all the stuff you've done do re-save the original document, but you can't because the history is lost.
This problem is still present in InDesign 2021
Sedrak Mkrtchyan commented
Same **** here. And searching online seemed it's only me who got this problem from version to version in InDesign.