Cursor and input not visible when re-pushing a ModalScreen

[phughes70]

Hi,
I'm trying to re-use the same ModalScreen instance each time the modal is requested so that it can retain it's state between views. This works apart from one thing - on the first push the modal works fine, but on subsequent pushes the modal does not display the input cursor or any input reaction at all. Inputs are being registered by the widgets, I can see them by returning them when the modal is dismissed, they are just not rendered on screen.

The modal I'm using has a number of selection lists used to pick filter criteria for a data table, but the problem is reproducible with simpler examples like the one below.

Is this meant to work? I'm new to textual so apologies if I'm missing something obvious.

Thanks.

from textual.app import App, ComposeResult
from textual.containers import Vertical
from textual.screen import ModalScreen
from textual.widgets import Footer, Header, Input


class Modal(ModalScreen[str]):
    def compose(self) -> ComposeResult:
        with Vertical():
            yield Input()

    def on_input_submitted(self):
        self.dismiss(self.query_one(Input).value)


class TestApp(App):
    # Using the same modal more than once ('m') shows the problem. Using a new
    # modal each time ('n') works fine.
    BINDINGS = [
        ("m", "modal", "Long life modal"),
        ("n", "new_modal", "New modal"),
    ]

    def __init__(
        self, driver_class=None, css_path=None, watch_css=False, ansi_color=False
    ):
        super().__init__(driver_class, css_path, watch_css, ansi_color)

        self.longLifeModal = Modal()

    def compose(self) -> ComposeResult:
        yield Header()
        yield Footer()

    def modalCallback(self, text: str | None) -> None:
        if text:
            self.notify(f"Modal returned: {text}")

    def action_modal(self) -> None:
        self.push_screen(self.longLifeModal, self.modalCallback)

    def action_new_modal(self) -> None:
        self.push_screen(Modal(), self.modalCallback)


if __name__ == "__main__":
    app = TestApp()
    app.run()

[TomJGooding]

I think there must be some "destruction" of your screen which effectively stops it from processing correctly, though I'm not 100% sure what the Textual code is doing from a quick skim.

If you explicitly install the screen instead, I think this works as expected?

[phughes70]

Yes, that works. Thanks for the quick response.

--- a/textual/test.py
+++ b/textual/test.py
@@ -14,8 +14,8 @@ class Modal(ModalScreen[str]):
 
 
 class TestApp(App):
-    # Using the same modal more than once ('m') shows the problem. Using a new
-    # modal each time ('n') works fine.
+    SCREENS = {"longLifeModal": Modal}
+
     BINDINGS = [
         ("m", "modal", "Long life modal"),
         ("n", "new_modal", "New modal"),
@@ -26,8 +26,6 @@ class TestApp(App):
     ):
         super().__init__(driver_class, css_path, watch_css, ansi_color)
 
-        self.longLifeModal = Modal()
-
     def compose(self) -> ComposeResult:
         yield Header()
         yield Footer()
@@ -37,7 +35,7 @@ class TestApp(App):
             self.notify(f"Modal returned: {text}")
 
     def action_modal(self) -> None:
-        self.push_screen(self.longLifeModal, self.modalCallback)
+        self.push_screen("longLifeModal", self.modalCallback)
 
     def action_new_modal(self) -> None:
         self.push_screen(Modal(), self.modalCallback)