<!-- See our full bug reporting guidelines at https://inkscape.org/contribute/report-bugs/ Writing a good bug report will ensure we'll be able to help efficiently. 🙂 --> #### Summary: Inkscape often crashes when I use Undo History. Usually there should be a longer list (10+ items), it happens more often if I import a PDF file and working with it, but can be reproduced with just objects too. #### Steps to reproduce: 1. Open Inkscape 1. Switch to rectangle tool (other shapes have this issue too) 1. draw one or more rectangles 1. change opacity using the bottom-left widget 1. draw one or more rectangles 1. Make sure both the Undo History dialog and Objects dialog are open 1. select the opacity item in the undo history list, then select the latest item (or any item after opacity) #### What happened? - Crash - These are minimal steps but often Inkscape would crash after the first click on 'Unchanged' step, if working with imported PDFs. It can take more clicks for it to crash. #### What should have happened? - no crash, the document state returns to the respective step. Sample attachments: I've made two backtraces, one for working with PDF and one for regular objects like stars. I've included errors that happened before the backtrace command too. [UndoHistoryCrashInkscape1.1_ObjectsOnly_backtrace.txt](/uploads/16e38cae4923ac1540936ba69ffb62aa/UndoHistoryCrashInkscape1.1_ObjectsOnly_backtrace.txt) [UndoHistoryCrashInkscape1.1_PDF_Import_backtrace.txt](/uploads/e70890126e73aff5e0b1aa4ae4d6199a/UndoHistoryCrashInkscape1.1_PDF_Import_backtrace.txt) Update: backtrace [inkscape_backtrace_1_1_x.txt](https://gitlab.com/inkscape/inbox/uploads/a169ec9ab4227d5eb65e6169e831f3e4/inkscape_backtrace_1_1_x.txt) from a personal build of Inkscape 1.1 (f559db2bc1, 2021-07-04) Linux Mint 20 (from comment https://gitlab.com/inkscape/inbox/-/issues/5114#note_631335302) Bisection info: 1. crash first introduced inkscape@8f9f4d48a9b986881507732527e1adf8b17d6c3c 1. crash on undo (i.e. from steps to replicate: clicking on opacity) at inkscape@8ce52c5d246800de959f697c0c22811d13f77bd4 1. crash on undo fixed in inkscape@7cb3280f886f7374592a22cacff1c0c00bdfed5f , MR has some info on the logics https://gitlab.com/inkscape/inkscape/-/merge_requests/1101 #### Version Info: ``` - Inkscape Version: Inkscape 1.1 (c4e8f9e, 2021-05-24) (happened in 1.0.2 too) - Operating System: Debian, Linux - Operating System version: Debian GNU/Linux bullseye/sid - Environment: LXDE, X11. ```