diff --git a/Known-issues.md b/Known-issues.md
index fd6acde..329cab8 100644
--- a/Known-issues.md
+++ b/Known-issues.md
@@ -1,4 +1,4 @@
 * **[All]** _Add directory_ button don't support multiselection. QT limitation.
-* **[Linux]** On some distributions _Add directory_ and _Add file_ button display additional black window. Cause unknown. QT bug?
+* **[Linux]** On some distributions using GTK window manager _Add directory_ and _Add file_ button display additional black window. QT bug.
 * **[Linux]** Lack of tray icon. Disabled intentionally due to multiple QT bugs.
 * **[OS X]** Saving last used path don't work. Qt bug. It will be fixed in next QT release.
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