I can think of 3 ways to do this (see below).
i tend to like the horizontal features in blue below at the top. its a common design and qlikview had limitations for this in ajax mode.
for vertical design you can use the red or green options. Yes you have some extra space in there . Horizontal design loses less space and is a good for adhoc.
Extensions are needed to start fine tuning the UI pixel by pixel but keep in mind you are always dealing with a flex/adjustable UI in Qlik Sense with extensions or not.
I've moved to trying to not use listboxes at all. In most of my application the required selections can be made by interacting with the visualizations, through smart search or with the selection tool (the icon next to search). Note, by default only the dimensions you have created show up. The users has to check "Show Fields" to have all the fields in the data model appear.
I don't use the 'no listbox' approach all the time but I have found with Qlik Sense the need for listboxes is less than QlikView so I'm always challenging myself if I really need listboxes or not.
Thank you Jonathan & Josh for your suggestions.
I have tried Filter pane / Listbox in QS but as you have shown in the above screenshot, it is created with a huge gap between two drop downs and due to this the space is getting wasted in the screen.
I also agree with Josh that there is a selections tool by default available, but for every app we build in QS we at least should need to display some of major / important selections in the screen for quick selections.
In Qlikview multibox, the design looks pretty good when compared to QS.
My question is how we can make similar layout as QV in QS.
I am also missing the multi-box from QlikView.
But to get rid of the space beteween the small filter panes, you can try an extension Xgrid Resize that allows you to double (at least) the grid density. Worked for me. Some times is tricky to convince the extension to do the grid resizing, but once it's done for 1 page, you can duplicate tjhat page further for other pages.
Once you have done the resizing, you can delete the object from that page and the resizing persists
I've also found this recentrly, but haven't tried it yet