On last tip (develop) i get almost the same problem that already reported below. Except that now the top left coordinate is kept good, but the height of the window recovered is constantly growing at each save/load turn.
I can confirm. With setUsingNativeTitleBar (false); (JUCE decorations) it keeps window sizes. But with “true” (when windowmanager decoration used) it increments window size by header and frame of WM every time.
Looks like it gets the size with WM header and borders, not just the content of the window.