Fixed painting issues with draggable tabs

This fixes a few of the remaining glitches tabbar animations have:
* We no longer grab tabs but paint them through QStyle. This makes tabs
work and animate correctly when they are outside the visible region.
* Buttons now correctly follow tabs when dropped
* Gtkstyle recieved some polish to make it look more native.

Task-number: 247694, 251166
Reviewed-by: nrc

1 files changed, 6 insertions, 3 deletions

diff --git a/src/gui/styles/qgtkstyle.cpp b/src/gui/styles/qgtkstyle.cpp
index 519fed7..541415f 100644
--- a/src/gui/styles/qgtkstyle.cpp
+++ b/src/gui/styles/qgtkstyle.cpp
@@ -2760,10 +2760,13 @@ void QGtkStyle::drawControl(ControlElement element,
             if (tab->state & State_Selected)
                 state = GTK_STATE_NORMAL;
 
-            bool first = tab->position == QStyleOptionTab::Beginning || tab->position == QStyleOptionTab::OnlyOneTab;
-            bool last = tab->position == QStyleOptionTab::End || tab->position == QStyleOptionTab::OnlyOneTab;
             bool selected = (tab->state & State_Selected);
-            if (option->direction == Qt::RightToLeft) {
+            bool first = false, last = false;
+            if (widget) {
+                // This is most accurate and avoids resizing tabs while moving
+                first = tab->rect.left() == widget->rect().left();
+                last = tab->rect.right() == widget->rect().right();
+            } else if (option->direction == Qt::RightToLeft) {
                 bool tmp = first;
                 first = last;
                 last = tmp;