Undoing after drawing polygons on geoboard changes the polygons

mrgordonmaths shared this problem 5 months ago
In Progress

Steps to reproduce as per video:

- create a geoboard with pegs (eg pegs = sequence(sequence((a, b), a, 1, 20), b, 1, 10))

- draw 3 triangles

- undo the last triangle

... wtf... the other 2 triangles change!

- 'redo' and the 3rd triangle comes back, looking totally different too

Pressing 'Esc' key while drawing a polygon also has this same effect.

This is my first time using Geogebra. I presume I'm not doing anything wrong? This seems like very strange, unexpected behaviour.

Comments (4)


Yes, there's something wrong :) in the app that isn't happening in the Classic versions 5 (installed - Windows).

In Classic v.6 (installed) the undo operation doesn't modify the other triangles, but the redo doesn't create the triangle correctly.

In online versions of all the apps, undo and redo mess up things.

I think that it's related to point capturing, but afaik point capturing shouldn't be enabled when the grid is not shown.

(so I'm both thinking loud, and also probably wrong)

Thank you, I'm looping your report to the developers.


Thanks for the speedy response, and glad to know I'm not going mad here! I've also noticed that if I save a file, then open it in a new tab/window, it looks incorrect as well (as if I just did the undo operation as per in the video). I'm also getting the same with other polygons, not just triangles.


Thanks we'll check (but we won't be able to fix this soon).

A better way to do this is to use the built-in grid (and set it to "fixed to grid")


la causa es que al hacer click en un punto de la lista de puntos el nuevo punto creado es definido como point(list) en lugar de point(list,parameter) así al deshacer se recupera un punto definido point(list) que puede ser recreado en otra posicion de la lista

no sé si es mejor que el punto que sea creado al hacer click en una lista de puntos fuese point(list) o point(list,parameter) o element(list,position)

tendría diversas capacidades de movilidad según cual fuese la definicion. en el caso 1 se puede mover por cualquier punto de la lista; en los otros casos ningun movimiento es permitido

© 2020 International GeoGebra Institute