Both are needed.

You may theoretically have a problem that can be reproduced only if you take actions in a specific order. For instance, if you would search for a word, go to a page and then see that highlighting does not work. But, if you would get to a page taking a different path, you would see that highlighting is working.

In an ideal world, you should try to check all the possible ways navigating to a page and all the required highlighting and notes to work there, but in reality, generally speaking, covering all the possible combinations is not practical (Combinatorial Explosion of test cases combinations). This is where the Pareto principle, customer demands, the importance of a feature, regression history, complexity, stakes and stakeholders might help to figure out the sufficient number of test cases for a feature.

Both are needed.

You may theoretically have a problem that can be reproduced only if you take actions in a specific order. For instance, if you would search for a word, go to a page and then see that highlighting does not work. But, if you would get to a page taking a different path, you would see that highlighting is working.

In an ideal world, you should try to check all the possible ways navigating to a page and all the required highlighting and notes to work there, but in reality, generally speaking, covering all the possible combinations is not practical (Combinatorial Explosion of test cases combinations). This is where the Pareto principle, customer demands, the importance of a feature, regression history, complexity, stakes and stakeholders might help to figure out the sufficient number of test cases for a feature.