Remove the size limitation of content-pane add-in's in Excel
In Excel desktop there is a limitation to the width a content pane can be resized when adjusting with the mouse. It appears to be approx 1000px. However, if the columns underneath the content pane are resized, the pane follows this adjustment and will become wider than the 1000px limitation imposed by mouse resize. However, if the content pane is then again resized with the mouse the width limitation kicks in again and the pane width snaps back.
In PowerPoint there is no such limitation to the width of a content pane Add-In. It would be helpful, and consistent, to remove the limitation imposed by mouse resizing of content panes in Excel.
Good news, some progress! Issue has been updated and the size limit has been increased to 2000px but with the same snapshot limitation. See recent comment https://github.com/OfficeDev/office-js/issues/391#issuecomment-541960386
FYI I have raised this in the Office JS Github issues https://github.com/OfficeDev/office-js/issues/391
Garry Lowther commented
In this era of add-ins and extensions, developers AND users want consistency. Both Microsoft and Google (and Microsoft with Edge Chromium) have imposed height and width limits of respective task panes and popups. This frustrates BOTH developers and their customers as they expect the same experience regardless of whether they are in Outlook or on another web site.
Please allow the manifest.xml to specify the width of the task pane.
Dave Haas commented
One additional comment. The limitation is not present in Excel Online.