It looks like it was the Shopify Planet app that was inserting ‘showmoreinfo’ with boolean value. I removed the app section from default page, and the issue has resolved.
Looks like Shopify need to fix something in their Planet app
Topic summary
Main issue: Creating a page template triggered the error “Setting ‘showMoreinfo’ must be a string” in both the code and theme editors. Multiple browsers were tried. Screenshots show the error dialog.
Diagnosis: The ‘showmoreinfo’ setting was set to a boolean (true) instead of a string, causing a validation mismatch. In theme settings, settings expecting text (string) cannot accept true/false booleans.
Root cause: The Shopify Planet app was injecting ‘showmoreinfo’ with a boolean value into the default page’s app section. This conflicted with the theme’s expected data type.
Resolution: Removing the Planet app section from the default page resolved the template creation error. The participant notes this likely requires a fix on the Planet app’s side.
Status and outcomes: Issue resolved by the user; no further action items within the thread. Suggested follow-up is for Shopify/Planet app maintainers to correct the setting type.