Attached is an example of the QT Designer with my issue. My goal is to get any content inside (in particular the lineEdit) to expand to the far right of QTabWidget its within.
If you notice I have the tab selected in the picture and it says there is no layout currently (as indicated by the red no smoking looking symbol on it). When I try to add a layout to it using the buttons above the tabs (for horizontal, vertical, grid, form, etc...), no matter what I do it doesn't change the tabs layout but changes the very top level widgets layout instead which I don't want because that is giving the QTabWidget its ability to take on whatever the size of the window is.
I tried giving a horizontal and vertical layout to the elements within the tab thinking that might work but it didn't work either as my next attached image shows. My hunch is because the tab has no layout, any layouts within will not be honored.

Any help is appreciated. I've spent hours and can't figure it out for the life of me...!

Below is the UI XML:
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>xMarket</class>
<widget class="QWidget" name="xMarket">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>737</width>
<height>421</height>
</rect>
</property>
<property name="sizePolicy">
<sizepolicy hsizetype="Preferred" vsizetype="Preferred">
<horstretch>0</horstretch>
<verstretch>0</verstretch>
</sizepolicy>
</property>
<property name="windowTitle">
<string>Form</string>
</property>
<property name="layoutDirection">
<enum>Qt::LeftToRight</enum>
</property>
<layout class="QHBoxLayout" name="horizontalLayout">
<item>
<widget class="QTabWidget" name="xMarketTabWidget">
<property name="layoutDirection">
<enum>Qt::LeftToRight</enum>
</property>
<widget class="QWidget" name="tab">
<attribute name="title">
<string>Tab 1</string>
</attribute>
<widget class="QLineEdit" name="lineEdit">
<property name="geometry">
<rect>
<x>240</x>
<y>30</y>
<width>113</width>
<height>21</height>
</rect>
</property>
</widget>
<widget class="QLabel" name="label">
<property name="geometry">
<rect>
<x>150</x>
<y>30</y>
<width>59</width>
<height>16</height>
</rect>
</property>
<property name="text">
<string>Search:</string>
</property>
</widget>
</widget>
<widget class="QWidget" name="tab_2">
<attribute name="title">
<string>Tab 2</string>
</attribute>
</widget>
</widget>
</item>
</layout>
</widget>
<resources/>
<connections/>
</ui>