Assignment

Thank you for the javascript code. That is a great help for me. The meaning is the same, but i tried to directly modify the template files and it worked to hide the review panel as default.
(Adding javascript code in Themes looks like a bit of work today according to $THEME->javascripts description in https://docs.moodle.org/dev/Themes_overview#Theme_options_2 .)

How i modifled the files is shown in diff:

# diff  mod/assign/templates/grading_app.mustache.orig  mod/assign/templates/grading_app.mustache
37c37
< <div data-region="review-panel">
---
> <div data-region="review-panel" class="collapsed">

# diff  mod/assign/templates/grading_actions.mustache.orig  mod/assign/templates/grading_actions.mustache
44,45c44,45
<        <button class="btn collapse-review-panel">{{#pix}} layout-expand-right, mod_assign, {{#str}} collapsereviewpanel, mod_assign {{/str}} {{/pix}}</button>
<        <button class="btn collapse-none active">{{#pix}} layout-default, mod_assign, {{#str}} defaultlayout, mod_assign {{/str}} {{/pix}}</button>
---
>        <button class="btn collapse-review-panel active">{{#pix}} layout-expand-right, mod_assign, {{#str}} collapsereviewpanel, mod_assign {{/str}} {{/pix}}</button>
>        <button class="btn collapse-none">{{#pix}} layout-default, mod_assign, {{#str}} defaultlayout, mod_assign {{/str}} {{/pix}}</button>