As @acaciomelo said
Actually the window size or state is saved by the browser itself, so if at the first time you let it maximized and when you open it again, it's going to be maximized too.
This situation you will face with mostly application which saves the position and size of window it was before close state.
So Best thing and realiable way to always maximiza the window at first (with UIpath you have Maximize Activity Available) it will take the cureent screen resolution size and maximize the window so everytime you will get the things at their places.
as @Masire said
and second thing i want to mention here
It is also an approach but you have to depend on the image of that icon and consider the case when if that icon will remove or not will be there.
So it is best practice if you are dealing with Uipath locally installed then use Open Application Activity and if you are dealing with Citrix based Automation then consider to run the “.exe” of that application by using Run explorer and Hot keys.