Hello, After checking the problem with Guille, we have the hypothesis of the source of the problem. We have seen that accessing Free Type is not thread-safe. Basically, the FTFace holds a structure that is filled up with the glyph and its information. As this structure is part of the Font Face (a font face is a font plus size and attributes), only one request to a glyph can be executed at the time. As we are sharing the same font in many places, you will be starting to see the problem. Also, we have seen that there many accesses to the glyphs outside the UI process. This problem started to appear as we starting to use Calypso (but it is not limited to it), as Calypso uses lazy tabs. The creation of these tabs is done outside the UI process. This is only a hack to test our hypothesis. To fix it correctly we will have to rewrite the drawing of the glyphs and synchronize the access to the glyph data information. Also, we want to do it in a way that does not penalize the processing in the UI process. I have only patched the code that is used by the rendering of morphic, other renderings like Athens or any other user using FT should be correctly rewritten. Once we are sure that synchronizing the access to FT fixes the problem, we will do a real fix not a dirty hack like this. I will be testing this new Image to see if there is an improvement. I will really love you try to use this image and tell me if you still find the problem. There is a PR generating a Pharo8 image (it is called wrong, but... it is a Pharo8) 32 bits ===== https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%20... 64 bits ===== https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%20... If somebody is willing to use it in Pharo 7, I can create a PR against Pharo7 to generate patched P7 images. Thanks! -- Pablo Tesone. tesonep@gmail.com