Fix width issues when un-maximizing Dolphin
Before this commit un-maximizing or to be more precise instantly changing the size of the window by a large amount could potentially change the width of the sidebars, the viewContainers and the window itself to unexpected/undesired widths.
This happened because the spacing calculation is triggered when the primary ViewContainer is resized but at this point in time some of the other widgets, especially the secondary ViewContainer and the navigatorsWidget have generally not been resized yet. Therefore the width and spacing calculations are based on partly updated and partly outdated values leading to wrong results.
This commit makes it so calculation of spacings is delayed until all widths have been updated.
Yes, spacing probably should not have the power to resize the window but unfortunately the spacing can not be set to be less forceful when taking space because otherwise the UrlNavigators will take all space they can get with their QSizePolicy::MinimumExpanding.
BUG: 430521 FIXED-IN: 21.08