diff --git a/color.go b/color.go
index 781e6a5..b50b2b6 100644
--- a/color.go
+++ b/color.go
@@ -5,6 +5,8 @@ import "image/color"
 // SelectColor displays the color selection dialog.
 //
 // Valid options: Title, Color, ShowPalette.
+//
+// May return: ErrCanceled.
 func SelectColor(options ...Option) (color.Color, error) {
 	return selectColor(applyOptions(options))
 }
diff --git a/entry.go b/entry.go
index ca571d8..011567e 100644
--- a/entry.go
+++ b/entry.go
@@ -4,6 +4,8 @@ package zenity
 //
 // Valid options: Title, Width, Height, OKLabel, CancelLabel, ExtraButton,
 // Icon, EntryText, HideText.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func Entry(text string, options ...Option) (string, error) {
 	return entry(text, applyOptions(options))
 }
diff --git a/file.go b/file.go
index 0ea5dab..5e15d4d 100644
--- a/file.go
+++ b/file.go
@@ -9,6 +9,8 @@ import (
 // SelectFile displays the file selection dialog.
 //
 // Valid options: Title, Directory, Filename, ShowHidden, FileFilter(s).
+//
+// May return: ErrCanceled.
 func SelectFile(options ...Option) (string, error) {
 	return selectFile(applyOptions(options))
 }
@@ -16,6 +18,8 @@ func SelectFile(options ...Option) (string, error) {
 // SelectFileMutiple displays the multiple file selection dialog.
 //
 // Valid options: Title, Directory, Filename, ShowHidden, FileFilter(s).
+//
+// May return: ErrCanceled, ErrUnsupported.
 func SelectFileMutiple(options ...Option) ([]string, error) {
 	return selectFileMutiple(applyOptions(options))
 }
@@ -24,6 +28,8 @@ func SelectFileMutiple(options ...Option) ([]string, error) {
 //
 // Valid options: Title, Filename, ConfirmOverwrite, ConfirmCreate, ShowHidden,
 // FileFilter(s).
+//
+// May return: ErrCanceled.
 func SelectFileSave(options ...Option) (string, error) {
 	return selectFileSave(applyOptions(options))
 }
diff --git a/list.go b/list.go
index 2c78313..75d7638 100644
--- a/list.go
+++ b/list.go
@@ -4,11 +4,15 @@ package zenity
 //
 // Valid options: Title, Width, Height, OKLabel, CancelLabel, ExtraButton,
 // Icon, DefaultItems, DisallowEmpty.
+//
+// May return: ErrCanceled, ErrExtraButton, ErrUnsupported.
 func List(text string, items []string, options ...Option) (string, error) {
 	return list(text, items, applyOptions(options))
 }
 
 // ListItems displays the list dialog.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func ListItems(text string, items ...string) (string, error) {
 	return List(text, items)
 }
@@ -17,11 +21,15 @@ func ListItems(text string, items ...string) (string, error) {
 //
 // Valid options: Title, Width, Height, OKLabel, CancelLabel, ExtraButton,
 // Icon, DefaultItems, DisallowEmpty.
+//
+// May return: ErrCanceled, ErrExtraButton, ErrUnsupported.
 func ListMultiple(text string, items []string, options ...Option) ([]string, error) {
 	return listMultiple(text, items, applyOptions(options))
 }
 
 // ListMultipleItems displays the list dialog, allowing multiple items to be selected.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func ListMultipleItems(text string, items ...string) ([]string, error) {
 	return ListMultiple(text, items)
 }
diff --git a/msg.go b/msg.go
index 48e20b1..7b1a830 100644
--- a/msg.go
+++ b/msg.go
@@ -4,6 +4,8 @@ package zenity
 //
 // Valid options: Title, Width, Height, OKLabel, CancelLabel, ExtraButton,
 // Icon, NoWrap, Ellipsize, DefaultCancel.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func Question(text string, options ...Option) error {
 	return message(questionKind, text, applyOptions(options))
 }
@@ -12,6 +14,8 @@ func Question(text string, options ...Option) error {
 //
 // Valid options: Title, Width, Height, OKLabel, ExtraButton, Icon,
 // NoWrap, Ellipsize.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func Info(text string, options ...Option) error {
 	return message(infoKind, text, applyOptions(options))
 }
@@ -20,6 +24,8 @@ func Info(text string, options ...Option) error {
 //
 // Valid options: Title, Width, Height, OKLabel, ExtraButton, Icon,
 // NoWrap, Ellipsize.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func Warning(text string, options ...Option) error {
 	return message(warningKind, text, applyOptions(options))
 }
@@ -28,6 +34,8 @@ func Warning(text string, options ...Option) error {
 //
 // Valid options: Title, Width, Height, OKLabel, ExtraButton, Icon,
 // NoWrap, Ellipsize.
+//
+// May return: ErrCanceled, ErrExtraButton.
 func Error(text string, options ...Option) error {
 	return message(errorKind, text, applyOptions(options))
 }
diff --git a/progress.go b/progress.go
index 281f56b..ecb32be 100644
--- a/progress.go
+++ b/progress.go
@@ -4,6 +4,8 @@ package zenity
 //
 // Valid options: Title, Width, Height, OKLabel, CancelLabel, ExtraButton,
 // Icon, MaxValue, Pulsate, NoCancel, TimeRemaining.
+//
+// May return: ErrUnsupported
 func Progress(options ...Option) (ProgressDialog, error) {
 	return progress(applyOptions(options))
 }
diff --git a/pwd.go b/pwd.go
index 5b31480..dd5b066 100644
--- a/pwd.go
+++ b/pwd.go
@@ -3,6 +3,8 @@ package zenity
 // Password displays the password dialog.
 //
 // Valid options: Title, OKLabel, CancelLabel, ExtraButton, Icon, Username.
+//
+// May return: ErrCanceled, ErrExtraButton, ErrUnsupported.
 func Password(options ...Option) (usr string, pwd string, err error) {
 	return password(applyOptions(options))
 }