When I ran tests on firefox with properties using Project Settings > Desired Capabilities I saw in console logs those lines in red:
Feb 06, 2020 3:46:13 PM org.openqa.selenium.remote.DesiredCapabilities firefox
INFO: Using `new FirefoxOptions()` is preferred to `DesiredCapabilities.firefox()`
Once the Firefox window poped up I opened ‘about:config’ and observed that the properties were not changed at all. Then I went to ‘about:profiles’ and verified that the Firefox instance was not opened with default profile.
I checked the logs again and found out that Firefox creates a temporary profile for Katalon test run:
1581000381591 mozrunner::runner INFO Running command: "C:\\Program Files\\Mozilla Firefox\\firefox.exe" "-marionette" "-foreground" "-no-remote" "-profile" "C:\\Users\\********\\AppData\\Local\\Temp\\rust_mozprofile.54TPwDbd8edt"
I tried to run Firefox with default profile instead and when I was looking for solution I came across this thread: Opening Firefox with a Specific, non anonymous profile - #15 by kazurayam and with few modifications to it this solved my issue.
The issue may be that initializing webdriver with ‘DesiredCapabilities.firefox()’ method is deprecated and Katalon did not updated it to the prefered one ‘new FirefoxOptions()’. Maybe I should report a bug for this.