Browser always shows 'is idle' while tests are actually running

[SevenOutman]

The banner only turns 'executing' when one of the running browsers finishes its tasks.

FYI I'm using karma-webpack as preprocessor for the test scripts. And a full list of plugins is as shown below:

"karma-chrome-launcher": "^3.1.0",
"karma-coverage": "^2.0.3",
"karma-firefox-launcher": "^2.1.1",
"karma-mocha": "^2.0.1",
"karma-mocha-reporter": "^2.2.5",
"karma-safarinative-launcher": "^1.1.0",
"karma-sinon-chai": "^2.0.2",
"karma-sourcemap-loader": "^0.3.8",
"karma-webpack": "^5.0.0",