Hey ! So I was going through this task and had a small doubt. How is this different from hide/show one level which is easily implemented by just numpad +/- ?
Is there a necessity for this kind of shortcut?

@Jacques Lucke (JacquesLucke) thank you so much for your help, I actually forgot to give display_previous a default value and that being the reason couldn't understand your idea.
I hope this diff is correct.
If you have any further requests or changes to be made, please do mention.
Thanks again !

As mentioned by @Jacques Lucke (JacquesLucke) , the changes have been made. And yes, initially display_previous was not initialised but this time it has been done.

Hey,
So I tried your suggestion but I think you have a wrong idea there. In that line I'm checking if prev_display exists (initially its -1/just declared). Its never equal to FILE_DEFAULTDISPLAY.
prev_display gets a value only when user changes his mode of view. If the user never changes his mode once he launches Blender, prev_display has no value.

Hey @Jacques Lucke (JacquesLucke) ,
I have made all the changes you have mentioned except the first one in line 243.
Why the below ?
use params->prevdisplay == FILE_DEFAULTDISPLAY and invert the condition.
(basically !( params->prevdisplay == FILE_DEFAULTDISPLAY ) right ?)
I tried it and didn't work. I also couldn't understand your logic behind this.Can you please explain this ?
Thanks in advance !

Okay so I have made the changes as @Brecht Van Lommel (brecht) mentioned. Also I do agree with @William Reynish (billreynish) that it keeps it simple and changes done are is to understand. But if it is really necessary to keep it globally per file type, some more details would be helpful as I'm not sure about text and properties editor.

Hey !
So I have come up with the patch D4479: Remember the last display mode in File Browser.
Any suggestions will be greatly appreciated.

So i have been working on this task for long time. Finding the file to change itself took most of my time because i am very much new to blender code. Now i think i need to change some parts in 'filesel.c' as this is where it checks for params->display.Can anyone guide me further about how will i store params->display once it is changed ?
Thanks in advance !

Hey Is this task done ?
If not, can I try it ?
Also any help would be really appreciated as I'm new to blender code.

Hey Thomas ,
I would like to debug this .
I am very new to contributing to blender and would love to learn.