Flexible page/filelist tree width in Typo3 8 by user specific setting.
Just use the following command in your Typo3 document root to download the extension from Github.
git clone "https://github.com/crealistiques/cre_pagetreewidth" typo3conf/ext/cre_pagetreewidth
Don't forget to install the extension in the Typo3 Extension Manager after fetching it.
The extension adds two new configuration fields to the Typo3 User Settings dialog. Both options are considered to change the standard width and sizing of the page and filelist tree.
In order to set a custom user specific width for the page/filelist tree section of the Typo3 backend, please go to the user settings tab "Edit and Advanced functions" and set your pixel based width in the field "Width of the page/filelist tree section". Save your changes and reload the backend to let the new setting take effect.
Please note: This setting has only an effect on larger screens greater than 991px.
The second option in the user settings, called "Width of page/filelist tree should be flexible in link and file browser dialogs", if activated, makes the width of the page/filelist tree section in modal and popup dialog windows more flexible. Within certain constraints the width now adapts to the tree content while preventing of ever getting wider than 66% of the width of the dialog on large screens. In combination with User TSConfig option "popupWindowSize" you could fully benefit from this option by setting a larger popup screen size – Typo3 default is 800x600 which might be too small on large screens.
options.popupWindowSize = 1200x900
or even e.g.
options.popupWindowSize = 1600x1200
depending on the screen size you are blessed with.
For those who are still using rtehtmlarea with Typo3 8 it might come in handy that modal dialogs opened by RTE HTML Area now get properly sized for optimal page/file tree dispaly, too.