[I] [Bug]: keyboard unresponsive during startup/shutdown of Hop GUI (hop)

["mattcasters (via GitHub)" <gi...@apache.org>]

mattcasters opened a new issue, #7421:
URL: https://github.com/apache/hop/issues/7421

   ### Apache Hop version?
   
   2.19
   
   ### Java version?
   
   OpenJDK 21
   
   ### Operating system
   
   Linux
   
   ### What happened?
   
   ### Description
   
   **Bug:**  
   When opening or closing the Hop GUI on Linux, keyboard input becomes completely unresponsive for 3–5 seconds everywhere in the desktop.  
   - Display and mouse cursor continue to work normally.  
   - Keystrokes are received by the kernel and buffered (type-ahead works — keys appear after the stall ends).  
   - Happens consistently on startup and shutdown.  
   - Mouse clicks still work and you can interact with other windows during the stall.
   
   **Environment**  
   - OS: Ubuntu 24.04 LTS (X11 session, GNOME)  
   - Desktop: GNOME on Xorg  
   - JVM flags used: `-Xmx8g` (high buffer/cache observed ~41 GB)  
   - Hop version: [please fill your exact version]  
   - Hop GUI loads a large number of plugins/libraries (typical for a full install)
   
   **Reproduction**  
   1. Start Hop GUI (`./hop-gui.sh`) or close it.  
   2. Immediately try typing anywhere (terminal, browser, etc.).  
   3. Keyboard is unresponsive for a few seconds while mouse/display remain fully responsive.
   
   **Root cause / Workaround that fixes it 100%**  
   Hop’s SWT/GTK startup (heavy JAR loading + widget creation + memory allocation) triggers a flood of calls to the AT-SPI accessibility bridge and IBus/GTK input framework. This temporarily blocks the X11 event dispatcher.  
   
   The following environment variables completely eliminate the stall:
   
   ```bash
   export NO_AT_BRIDGE=1          # disable accessibility bridge
   export GTK_IM_MODULE=xim       # use simple XIM instead of IBus
   export IBUS_DISABLE=1          # disable IBus for this process
   
   ### Issue Priority
   
   Priority: 3
   
   ### Issue Component
   
   Component: Hop Gui


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Re: [I] [Bug]: keyboard unresponsive during startup/shutdown of Hop GUI (hop)

["mattcasters (via GitHub)" <gi...@apache.org>]

mattcasters closed issue #7421: [Bug]: keyboard unresponsive during startup/shutdown of Hop GUI
URL: https://github.com/apache/hop/issues/7421


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Re: [I] [Bug]: keyboard unresponsive during startup/shutdown of Hop GUI (hop)

["mattcasters (via GitHub)" <gi...@apache.org>]

mattcasters commented on issue #7421:
URL: https://github.com/apache/hop/issues/7421#issuecomment-4883872738

   In the end it was indeed caused by the `ibus` process getting overwhelmed with the switching between IntelliJ and Hop GUI, but the solution was to simply run `ibus restart`.


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