TYPO3 Core

When saving an extension's configuration, the EM first reads the default configuration and the existing configuration, then merges the two (the newly saved configuration is then merged on top of that). The merging of default and existing configuration fails because they don't have the same structure. The existing configuration only contains configurations keys and values, whereas values are found under the "value" key in the default configuration.

The "value" dimension must be added to the existing configuration.

Note: this bug is visible only when saving the configuration of an extension with multiple subcategories. When there is a single subcategory, the bug does not happen because all values are read properly when presenting the form to the user and all (modified) values are also sent back for saving.

An extension with multiple subcategories is external_import, for example.