Dominik Bartholdi It's not actually needed to change anything, just opening the configuration page and saving again, makes this happen.

This automated test reproduces the issue:

@Test
    public void sameFolderPropertyAfterConfiguration() throws Exception {
        Folder f1 = createFolder();
        ConfigFileStore store = getStore(f1);

        r.configRoundtrip(f1);

        assertThat(store, Matchers.is(getStore(f1)));
    }

I think it's related with AbstractFolder because the properties are not being sent in the json after configuring.

I am not sure of why though. Maybe they are "invisible" properties?

Code changed in jenkins
User: imod
Path:
src/test/java/org/jenkinsci/plugins/configfiles/folder/FolderConfigFileActionTest.java
http://jenkins-ci.org/commit/config-file-provider-plugin/679be2283e7bf812745d6278edcfdf5533a0b4d9
Log:
JENKINS-42389 add test case to demonstrate problem

Evaristo Gutierrez I also asked on the ML for some hints on how to resolve this issue - unfortunate with no luck  

...maybe you could ask around internally?

Dominik Bartholdi sure, let me try and will come back to you.

My suggestion on the list was to make FolderConfigFileProperty a ReconfigurableDescribable.

hmm, strange that never made to my mailbox  - thanks!

Code changed in jenkins
User: imod
Path:
src/main/java/org/jenkinsci/plugins/configfiles/folder/FolderConfigFileProperty.java
http://jenkins-ci.org/commit/config-file-provider-plugin/3a4282fe3ead6de1de1d3b8034646083f1dfc380
Log:
[FIXED JENKINS-42389] implement ReconfigurableDescribable to fix data lost when folder gets updated

Code changed in jenkins
User: imod
Path:
src/main/java/org/jenkinsci/plugins/configfiles/folder/FolderConfigFileProperty.java
src/test/java/org/jenkinsci/plugins/configfiles/folder/FolderConfigFileActionTest.java
http://jenkins-ci.org/commit/config-file-provider-plugin/f7206995991ee2cbbc2dca750aee2290609f994f
Log:
Merge branch 'JENKINS-42389'

Compare: https://github.com/jenkinsci/config-file-provider-plugin/compare/dbda7551cec1...f7206995991e