Layout editor window does not remember position and size

[kannes]

Describe the bug
The Layout editor window (where you can add a map, legend, etc to blank pages) does not remember its position or size. This can be quite annoying if you have to resize it every time you open it.

How to Reproduce

1. Create a new layout
2. Move the Layout editor window somewhere and scale it as you like
3. Close the Layout editor window
4. Open the layout again
5. Notice how the window is not where you put it nor how you scaled it

QGIS and OS versions

QGIS version	3.10.0-A Coruña	QGIS code revision	6c816b4
Compiled against Qt	5.11.2	Running against Qt	5.11.2
Compiled against GDAL/OGR	2.4.1	Running against GDAL/OGR	2.4.1
Compiled against GEOS	3.8.0-CAPI-1.13.1	Running against GEOS	3.8.0-CAPI-1.13.1
Compiled against SQLite	3.29.0	Running against SQLite	3.29.0
PostgreSQL Client Version	11.5	SpatiaLite Version	4.3.0
QWT Version	6.1.3	QScintilla2 Version	2.10.8
Compiled against PROJ	5.2.0	Running against PROJ	Rel. 5.2.0, September 15th, 2018
OS Version	Windows 10 (10.0)

[gioman]

3.10.0-A Coruña

@kannes this is too old, please test also on the latest 3.10 available.

[kannes]

Same behaviour in a version from ~six weeks ago.

QGIS version	3.13.0-Master	QGIS code revision	af1576a
Compiled against Qt	5.14.2	Running against Qt	5.14.2
Compiled against GDAL/OGR	3.0.4	Running against GDAL/OGR	3.0.4
Compiled against GEOS	3.8.0-CAPI-1.13.1	Running against GEOS	3.8.0-CAPI-1.13.1
Compiled against SQLite	3.31.1	Running against SQLite	3.32.1
PostgreSQL Client Version	12.2	SpatiaLite Version	4.3.0a
QWT Version	6.1.4	QScintilla2 Version	2.11.4
Compiled against PROJ	6.3.1	Running against PROJ	Rel. 6.3.1, February 10th, 2020
OS Version	Arch Linux

[kannes]

Thank you @nyalldawson <3