Edit select coins message (send/build tab)
MODIFY
WalletWasabi.Gui/Controls/WalletExplorer/SendTabView.xaml
WalletWasabi.Gui/Controls/WalletExplorer/SendTabView.xaml
<Grid Classes="content">
<DockPanel LastChildFill="True" Margin="20">
<StackPanel DockPanel.Dock="Bottom" Margin="0 10" Spacing="10" HorizontalAlignment="Left">
- <TextBlock>You must select coins you want to spend from.</TextBlock>
+ <TextBlock>Select coins you want to spend.</TextBlock>
<controls:ExtendedTextBox Classes="monospaceFont" Text="{Binding Address}" Watermark="Address" UseFloatingWatermark="True">
<i:Interaction.Behaviors>
<behaviors:PasteAddressOnClickBehavior Command="{Binding OnAddressPasteCommand}" />

Edit select coins message (send/build tab)