Mac Apps (Preview & Grab) won't stay open

[mintra]

Unless I have like one window opens, Preview and Grab app automatically quits after a very short inactivity. Is there a way to set it to stay open no matter if there's any active window open? I never had this problem before upgrading to Yosemite. Thank you.

 

[Taz Mangus]

Unless I have like one window opens, Preview and Grab app automatically quits after a very short inactivity. Is there a way to set it to stay open no matter if there's any active window open? I never had this problem before upgrading to Yosemite. Thank you.

Try this:

• Open Disk Utility and Repair Permissions. Reboot.
• Open your user account Library folder, drag the Caches folder to the trash and reboot.

EDIT: I did not understand what the issue was until TETENAL's post below. Yes, it is by design.

 

[TETENAL]

That is by design and has been like that in since Lion.

You need to right click the app in the Dock an select "Keep it in the Dock" to quickly activate the app again when it quit.