Xamarin Global Variable in XAML doesn't refresh until later (randomly) - xaml

Question

I have 3 global variables in my app.xaml.cs.
public static bool _Code { get; set; }
public static bool _Full { get; set; }
public static bool _Common { get; set; }
I have code in a list that uses these variables to hide/show buttons.
<Grid>
<Label
Padding="4"
BackgroundColor="{DynamicResource ColorWindowBackground}"
HorizontalOptions="FillAndExpand"
IsVisible="{Binding Path=_Code, Source={x:DynamicResource Application.Current}}"
Text="{Binding CodeName}"
VerticalOptions="FillAndExpand" />
<Label
Padding="4"
BackgroundColor="{DynamicResource ColorWindowBackground}"
HorizontalOptions="FillAndExpand"
IsVisible="{Binding Path=_Full, Source={x:DynamicResource Application.Current}}"
Text="{Binding FullName}"
VerticalOptions="FillAndExpand" />
<Label
Padding="4"
BackgroundColor="{DynamicResource ColorWindowBackground}"
HorizontalOptions="FillAndExpand"
IsVisible="{Binding Path=_Common, Source={x:DynamicResource Application.Current}}"
Text="{Binding CommonName}"
VerticalOptions="FillAndExpand" />
</Grid>
I change these variables on another page.
private string selectedDisplayType;
public string SelectedDisplayType
{
get { return selectedDisplayType; }
set
{
if (value != selectedDisplayType)
{
SetProperty(ref selectedDisplayType, value);
if (selectedDisplayType != null)
{
//Update the Ui bools for showing the different types
if (SelectedDisplayType == DisplayType.Common.ToString())
{
SelectorEventObj.Common = true;
App._Code = false;
App._Common = true;
App._Full = false;
}
else if (SelectedDisplayType == DisplayType.Code.ToString())
{
SelectorEventObj.Code = true;
App._Code = true;
App._Common = false;
App._Full = false;
}
else
{
SelectorEventObj.Full = true;
App._Code = false;
App._Common = false;
App._Full = true;
}
}
}
}
However, when I go back to my page. The new button doesn't appear with the different values for the species.
If I click through the app a little, it appears after a random number of moves.
Is there something I need to do to let my model know that the Global Variable has changed?