[This is a Plasma 5 thing, it always worked for me on Plasma 4.]

To start with: I love, and use, the Desktop Search and Launch for many icons, to start programmes, do settings, etc. 
I have arranged those icons in a specific manner across my screen (1920x1200). I even locked the widgets.

Sometimes, I am restricted to the internal screen, 1440xsomething. Then the nicely arranged icons get pushed to the left and top; not scaled. 
And when I return to my larger screen, the icons are still there, squeezed to the left and top in an ugly manner. 

No question, the expected behaviour is for them to return to the original settings. I can't and wouldn't want to redo all these twice a week; I think this is understandable. 

On Plasma 4 this problem did not occur.