Changed made onBeforeShow are applied for parent browser screen instead of editor

[glebfox]

Environment

Jmix version: 1.5.5

Bug Description

Origin: forum

Inside the onBeforeShow listener of an edit screen, if a user modify the editedEntity, the changes are made on the parent browser screen.

Steps To Reproduce

1. Add the following code to UserEditor

@Subscribe
public void onBeforeShow(final BeforeShowEvent event) {
    getEditedEntity().setFirstName("TEST");
}

2. Open an entity for editing
3. Close without saving

Current Behavior

1. Changed made in onBeforeShow event listener are not applied to the edited entity
2. Entity isn't marked as modified
3. The changes are made on the parent browser screen

Expected Behavior

Entity in the BrowserScreen is not changed