I am working on developing a theme. I overrode the default.xml layout file for theme in my, VENDOR/THEME/Magento_Theme/layout/override/base/default.xml. In this file, I have defined some overrides which works fine with other modules, except the CatalogSearch module. When I try to search anything on my theme, it gives me page with blank / null layout. To get the theme specific changes on the search result page, I need to create CatalogSearch module and copy the changes from the override/base/default.xml file and place them to VENDOR/THEME/Magento_CatalogSearch/layout/catalogsearch_result_index.xml file. I do not know why the layout does not work with search but works well with all other modules.
NOTE: I found that , for some reason, the common items which are defined to be displayed on every page for the theme and defined in default.xml file in other modules; are not displayed on search result page. Do I need to tweak anything on catalogseach_result_index.xml file to pick stuff specified in default.xml files?
Thanks in advance.