Horrible hack to avoid Forge stealing keyboard input in terminal screens.

src/main/java/li/cil/oc2/client/gui/AbstractMachineTerminalScreen.java

@@ -9,9 +9,11 @@ import li.cil.oc2.common.Constants;
 import li.cil.oc2.common.container.AbstractMachineTerminalContainer;
 import li.cil.oc2.common.util.TooltipUtils;
 import net.minecraft.ChatFormatting;
+import net.minecraft.client.gui.components.EditBox;
 import net.minecraft.client.renderer.GameRenderer;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.chat.FormattedText;
+import net.minecraft.network.chat.TextComponent;
 import net.minecraft.network.chat.TranslatableComponent;
 import net.minecraft.world.entity.player.Inventory;
 import net.minecraftforge.api.distmarker.Dist;
@@ -103,6 +105,10 @@ public abstract class AbstractMachineTerminalScreen<T extends AbstractMachineTer
         super.init();
         terminalWidget.init();
 
+        final EditBox focusIndicatorEditBox = new EditBox(font, 0, 0, 0, 0, TextComponent.EMPTY);
+        focusIndicatorEditBox.setFocus(true);
+        setFocusIndicatorEditBox(focusIndicatorEditBox);
+
         addRenderableWidget(new ToggleImageButton(
             this, leftPos - Sprites.SIDEBAR_3.width + 4, topPos + CONTROLS_TOP + 4,
             12, 12,
@@ -168,6 +174,11 @@ public abstract class AbstractMachineTerminalScreen<T extends AbstractMachineTer
 
     ///////////////////////////////////////////////////////////////////
 
+    // We use this text box to indicate to Forge that we want all input, and event handlers should not be allowed
+    // to steal input from us (e.g. via custom key bindings). Since Forge is lazy and just uses getDeclaredFields
+    // to get private fields, which completely skips fields in base classes, we require subclasses to hold the field...
+    protected abstract void setFocusIndicatorEditBox(final EditBox editBox);
+
     @Override
     protected void renderBg(final PoseStack stack, final float partialTicks, final int mouseX, final int mouseY) {
         RenderSystem.setShader(GameRenderer::getPositionTexShader);

src/main/java/li/cil/oc2/client/gui/ComputerTerminalScreen.java

@@ -1,6 +1,7 @@
 package li.cil.oc2.client.gui;
 
 import li.cil.oc2.common.container.ComputerTerminalContainer;
+import net.minecraft.client.gui.components.EditBox;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.entity.player.Inventory;
 import net.minecraftforge.api.distmarker.Dist;
@@ -8,7 +9,18 @@ import net.minecraftforge.api.distmarker.OnlyIn;
 
 @OnlyIn(Dist.CLIENT)
 public final class ComputerTerminalScreen extends AbstractMachineTerminalScreen<ComputerTerminalContainer> {
+    @SuppressWarnings("all") private EditBox focusIndicatorEditBox;
+
+    ///////////////////////////////////////////////////////////////////
+
     public ComputerTerminalScreen(final ComputerTerminalContainer container, final Inventory playerInventory, final Component title) {
         super(container, playerInventory, title);
     }
+
+    ///////////////////////////////////////////////////////////////////
+
+    @Override
+    protected void setFocusIndicatorEditBox(final EditBox editBox) {
+        focusIndicatorEditBox = editBox;
+    }
 }

src/main/java/li/cil/oc2/client/gui/RobotTerminalScreen.java

@@ -3,6 +3,7 @@ package li.cil.oc2.client.gui;
 import com.mojang.blaze3d.systems.RenderSystem;
 import com.mojang.blaze3d.vertex.PoseStack;
 import li.cil.oc2.common.container.RobotTerminalContainer;
+import net.minecraft.client.gui.components.EditBox;
 import net.minecraft.client.renderer.GameRenderer;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.entity.player.Inventory;
@@ -16,6 +17,10 @@ public final class RobotTerminalScreen extends AbstractMachineTerminalScreen<Rob
 
     ///////////////////////////////////////////////////////////////////
 
+    @SuppressWarnings("all") private EditBox focusIndicatorEditBox;
+
+    ///////////////////////////////////////////////////////////////////
+
     public RobotTerminalScreen(final RobotTerminalContainer container, final Inventory playerInventory, final Component title) {
         super(container, playerInventory, title);
     }
@@ -36,4 +41,11 @@ public final class RobotTerminalScreen extends AbstractMachineTerminalScreen<Rob
         RobotContainerScreen.renderSelection(stack, menu.getRobot().getSelectedSlot(), leftPos + SLOTS_X + 4, topPos + SLOTS_Y + 4, 12);
         renderTooltip(stack, mouseX, mouseY);
     }
+
+    ///////////////////////////////////////////////////////////////////
+
+    @Override
+    protected void setFocusIndicatorEditBox(final EditBox editBox) {
+        focusIndicatorEditBox = editBox;
+    }
 }