When entering and exiting full screen mode from a maximized window twice, the original window settings are lost. Specifically, the window is moved right and down, and the menu bar/status bar are hidden.

Reproducible: Always

Steps to Reproduce:
1. Start Digikam. It is assumed that the menu bar is visible (Menubar=Enabled in digikamrc or missing)
2. Ensure the Digikam main window is maximized
3. Press "Ctrl+Shift+F" FOUR times (enter and exit full screen mode twice)

Actual Results:  
After exiting full screen the second time, the window position is changed (moved to right about 30% of the screen and down about 20% of the screen), width and hight are the same as for a maximized window (so it drops off the screen). The menu bar and status bar are no longer visible. The only way to enable the menu bar again is by editing digikamrc (because Ctrl+M doesn't work, see #365929) and adding the line "MenuBar=Enabled" to the [General Settings] section. 


Expected Results:  
After exiting full screen mode, the window settings from before should be restored, i.e. a  maximized window and visible toolbar and menu bar.

I think the source of the bug is the way digikamrc is updated after entering/exiting full screen mode. I copied the contents of the [General Settings] section after each press of Ctrl+Shift+F in step 3 above.

Initial settings, before step 3.

[General Settings]
Application Style=Fusion
Apply Sidebar Changes Directly=false
FullScreen Hide SideBars=false
FullScreen Hide ThumbBar=true
FullScreen Hide ToolBars=false
Height 900=874
Icon Theme=
Scroll Current Item To Center=false
Show Permanent Delete Dialog=true
Show Splash=true
Show Trash Delete Dialog=true
State=AAAA/wAAAAD9AAAAAAAABkAAAALuAAAABAAAAAQAAAAIAAAACPwAAAABAAAAAgAAAAEAAAAWAG0AYQBpAG4AVABvAG8AbABCAGEAcgEAAAAA/////wAAAAAAAAAA
String Comparison Type=0
ToolBarsMovable=Disabled
Use Large Thumbs=false
Use Trash=false
Version=5.0.0
Width 1600=1596
Window-Maximized 900x1600=true

After going to full screen mode the first time. Remark the added lines "MenuBar=Disabled" and "StatusBar=Disabled"

[General Settings]
Application Style=Fusion
Apply Sidebar Changes Directly=false
FullScreen Hide SideBars=false
FullScreen Hide ThumbBar=true
FullScreen Hide ToolBars=false
Height 900=900
Icon Theme=
MenuBar=Disabled
Scroll Current Item To Center=false
Show Permanent Delete Dialog=true
Show Splash=true
Show Trash Delete Dialog=true
State=AAAA/wAAAAD9AAAAAAAABkAAAANcAAAABAAAAAQAAAAIAAAACPwAAAABAAAAAgAAAAEAAAAWAG0AYQBpAG4AVABvAG8AbABCAGEAcgEAAAAA/////wAAAAAAAAAA
StatusBar=Disabled
String Comparison Type=0
ToolBarsMovable=Disabled
Use Large Thumbs=false
Use Trash=false
Version=5.0.0
Width 1600=1600

After exiting full screen mode the first time. Remark that at this time, the menu and status bar are still visible and the lines "MenuBar=Disabled" and "StatusBar=Disabled" are gone.

[General Settings]
Application Style=Fusion
Apply Sidebar Changes Directly=false
FullScreen Hide SideBars=false
FullScreen Hide ThumbBar=true
FullScreen Hide ToolBars=false
Height 900=900
Icon Theme=
Scroll Current Item To Center=false
Show Permanent Delete Dialog=true
Show Splash=true
Show Trash Delete Dialog=true
State=AAAA/wAAAAD9AAAAAAAABkAAAALuAAAABAAAAAQAAAAIAAAACPwAAAABAAAAAgAAAAEAAAAWAG0AYQBpAG4AVABvAG8AbABCAGEAcgEAAAAA/////wAAAAAAAAAA
String Comparison Type=0
ToolBarsMovable=Disabled
Use Large Thumbs=false
Use Trash=false
Version=5.0.0
Width 1600=1600
Window-Maximized 900x1600=true

After going to full screen the second time:

[General Settings]
Application Style=Fusion
Apply Sidebar Changes Directly=false
FullScreen Hide SideBars=false
FullScreen Hide ThumbBar=true
FullScreen Hide ToolBars=false
Height 900=900
Icon Theme=
MenuBar=Disabled
Scroll Current Item To Center=false
Show Permanent Delete Dialog=true
Show Splash=true
Show Trash Delete Dialog=true
State=AAAA/wAAAAD9AAAAAAAABkAAAANcAAAABAAAAAQAAAAIAAAACPwAAAABAAAAAgAAAAEAAAAWAG0AYQBpAG4AVABvAG8AbABCAGEAcgEAAAAA/////wAAAAAAAAAA
StatusBar=Disabled
String Comparison Type=0
ToolBarsMovable=Disabled
Use Large Thumbs=false
Use Trash=false
Version=5.0.0
Width 1600=1600

After exiting full screen the second time. The window position is changed (moved to right about 30% of the screen and down about 20% of the screen), width and hight are the same as for a maximized window (so it drops off the screen). The menu bar and status bar are not restored, the lines "MenuBar=Disabled" and "StatusBar=Disabled" are still present.

[General Settings]
Application Style=Fusion
Apply Sidebar Changes Directly=false
FullScreen Hide SideBars=false
FullScreen Hide ThumbBar=true
FullScreen Hide ToolBars=false
Height 900=874
Icon Theme=
MenuBar=Disabled
Scroll Current Item To Center=false
Show Permanent Delete Dialog=true
Show Splash=true
Show Trash Delete Dialog=true
State=AAAA/wAAAAD9AAAAAAAABjwAAANCAAAABAAAAAQAAAAIAAAACPwAAAABAAAAAgAAAAEAAAAWAG0AYQBpAG4AVABvAG8AbABCAGEAcgEAAAAA/////wAAAAAAAAAA
StatusBar=Disabled
String Comparison Type=0
ToolBarsMovable=Disabled
Use Large Thumbs=false
Use Trash=false
Version=5.0.0
Width 1600=1596